Pub Date : 2025-11-01Epub Date: 2025-03-28DOI: 10.1016/j.aosl.2025.100616
Haojie Wu , Haipeng Yu , Xin Wang , Shanling Cheng , Yunsai Zhu , Hongyu Luo
Previous studies have indicated a global reversal of near-surface wind speeds from a declining trend to an increasing trend around 2010; however, it remains unclear whether upper-air wind speeds exhibit a similar reversal. This study evaluates reanalysis products using surface and radiosonde observations to analyze upper-air wind speed variations in the Northern Hemisphere, focusing on their seasonal and latitudinal differences. Results demonstrate that JRA-55 effectively captures wind speed variations in the Northern Hemisphere. Notably, upper-air wind speeds over land experienced a reversal in winter 2010 with significant latitudinal differences. The trend reversal of upper wind speed between the midlatitudes and subtropics presents a dipole pattern. From 1990 to 2010, upper-air wind speeds in the midlatitudes (40°–70°N) significantly declined, while the subtropical zone (20°–40°N) displayed an opposite trend. However, during 2010–2020, wind speeds in the midlatitudes shifted to a significant positive trend, whereas the subtropics experienced a significant negative trend. The variations in Northern Hemisphere winter wind speeds can be attributed to changes in low-level baroclinicity driven by tropical diabatic heating and midlatitude transient eddy feedback. Enhanced diabatic heating and weakened eddy feedback during 1990–2010 contributed to reduced wind speeds in the midlatitudes and increased speeds in the subtropics, while reduced diabatic heating and strengthened eddy feedback during 2010–2020 resulted in increased wind speeds in the midlatitudes and decreased speeds in the subtropics. The reversal of upper-air wind speeds could affect surface wind speeds by downward momentum transfer, which could contribute to the reversal of surface wind speeds.
{"title":"A reversal of upper-air wind speed in the Northern Hemisphere","authors":"Haojie Wu , Haipeng Yu , Xin Wang , Shanling Cheng , Yunsai Zhu , Hongyu Luo","doi":"10.1016/j.aosl.2025.100616","DOIUrl":"10.1016/j.aosl.2025.100616","url":null,"abstract":"<div><div>Previous studies have indicated a global reversal of near-surface wind speeds from a declining trend to an increasing trend around 2010; however, it remains unclear whether upper-air wind speeds exhibit a similar reversal. This study evaluates reanalysis products using surface and radiosonde observations to analyze upper-air wind speed variations in the Northern Hemisphere, focusing on their seasonal and latitudinal differences. Results demonstrate that JRA-55 effectively captures wind speed variations in the Northern Hemisphere. Notably, upper-air wind speeds over land experienced a reversal in winter 2010 with significant latitudinal differences. The trend reversal of upper wind speed between the midlatitudes and subtropics presents a dipole pattern. From 1990 to 2010, upper-air wind speeds in the midlatitudes (40°–70°N) significantly declined, while the subtropical zone (20°–40°N) displayed an opposite trend. However, during 2010–2020, wind speeds in the midlatitudes shifted to a significant positive trend, whereas the subtropics experienced a significant negative trend. The variations in Northern Hemisphere winter wind speeds can be attributed to changes in low-level baroclinicity driven by tropical diabatic heating and midlatitude transient eddy feedback. Enhanced diabatic heating and weakened eddy feedback during 1990–2010 contributed to reduced wind speeds in the midlatitudes and increased speeds in the subtropics, while reduced diabatic heating and strengthened eddy feedback during 2010–2020 resulted in increased wind speeds in the midlatitudes and decreased speeds in the subtropics. The reversal of upper-air wind speeds could affect surface wind speeds by downward momentum transfer, which could contribute to the reversal of surface wind speeds.</div><div>摘要</div><div>以往研究表明, 全球近地面风速已从下降趋势转为上升趋势; 然而目前尚不清楚高空风速是否也出现了类似的逆转. 本研究发现北半球冬季高空风速在2010年前后也存在逆转现象, 且该现象在中纬度和副热带之间形成了偶极子模态. 从1990年到2010年, 中纬度地区的高空风速显著减弱, 而副热带地区则表现为增强趋势; 在2010–2020年期间, 风速呈现出相反的趋势. 进一步分析表明, 这一逆转现象与热带非绝热加热和中纬度瞬变涡旋反馈所驱动的低层斜压性异常密切相关. 值得注意的是, 高空风速的逆转可能通过动量下传机制影响近地面风速, 这为解释同期地面风速的趋势逆转提供了参考依据.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100616"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-03-12DOI: 10.1016/j.aosl.2025.100614
Issa Rwambo , Yi Fan , Peilong Yu , Changyu Chu , Matthews Nyasulu , Philemon King'uza
Tanzania is mainly subject to a bimodal rainfall pattern, characterized by two distinct seasons: the long rains, occurring from March to May, and the short rains, which typically take place from October to December (OND). Short rains are usually less intense but still significantly influence local agriculture. Therefore, with station-based observations and reanalysis data, the current paper examines the interannual variability of OND precipitation in Tanzania from 1993 to 2022 and explores the possible impacts from El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) as well as the mechanisms. It is found that the Tanzania OND precipitation is above (below) normal in 1997, 2006, 2011, and 2019 (1993, 1998, 2005, and 2016). The composite difference between wet (dry) years and the climatology indicates that the anomalous lower-level convergence (divergence) and upward (downward) motion are the critical circulation characters for above (below) precipitation. Further analysis indicates ENSO and the IOD are the two main oceanic systems modulating OND precipitation in Tanzania. El Niño and a positive IOD could induce easterly anomalies and weaken the Walker circulation over the Indian Ocean, consequently leading to lower-level convergence in water vapor flux, upward anomalies, and more than normal precipitation in Tanzania. In contrast, La Niña and a negative IOD produce opposite circulation anomalies and less than normal precipitation over Tanzania. Moreover, through partial correlation and Generalized Equilibrium Feedback Analysis, the individual contributions of ENSO and the IOD to circulation are investigated. It is found that although both the IOD and ENSO impact the Walker circulation, the feedback to the IOD is stronger than ENSO. These results provide critical insights into the oceanic drivers and their mechanistic pathways underlying precipitation anomalies in Tanzania.
{"title":"Interannual variability of short rains in Tanzania and the influences from ENSO and the Indian Ocean Dipole","authors":"Issa Rwambo , Yi Fan , Peilong Yu , Changyu Chu , Matthews Nyasulu , Philemon King'uza","doi":"10.1016/j.aosl.2025.100614","DOIUrl":"10.1016/j.aosl.2025.100614","url":null,"abstract":"<div><div>Tanzania is mainly subject to a bimodal rainfall pattern, characterized by two distinct seasons: the long rains, occurring from March to May, and the short rains, which typically take place from October to December (OND). Short rains are usually less intense but still significantly influence local agriculture. Therefore, with station-based observations and reanalysis data, the current paper examines the interannual variability of OND precipitation in Tanzania from 1993 to 2022 and explores the possible impacts from El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) as well as the mechanisms. It is found that the Tanzania OND precipitation is above (below) normal in 1997, 2006, 2011, and 2019 (1993, 1998, 2005, and 2016). The composite difference between wet (dry) years and the climatology indicates that the anomalous lower-level convergence (divergence) and upward (downward) motion are the critical circulation characters for above (below) precipitation. Further analysis indicates ENSO and the IOD are the two main oceanic systems modulating OND precipitation in Tanzania. El Niño and a positive IOD could induce easterly anomalies and weaken the Walker circulation over the Indian Ocean, consequently leading to lower-level convergence in water vapor flux, upward anomalies, and more than normal precipitation in Tanzania. In contrast, La Niña and a negative IOD produce opposite circulation anomalies and less than normal precipitation over Tanzania. Moreover, through partial correlation and Generalized Equilibrium Feedback Analysis, the individual contributions of ENSO and the IOD to circulation are investigated. It is found that although both the IOD and ENSO impact the Walker circulation, the feedback to the IOD is stronger than ENSO. These results provide critical insights into the oceanic drivers and their mechanistic pathways underlying precipitation anomalies in Tanzania.</div><div>摘要</div><div>坦桑尼亚降水模态呈现双峰型, 其显著特征为两个不同的雨季: 长雨季 (3月至5月) 和短雨季 (10月至12月 (OND)). 短雨季降水强度通常较弱, 但对当地农业仍具有重要影响. 基于站点观测和再分析数据, 本文研究了1993–2022年坦桑尼亚OND降水的年际变化特征, 并探讨了厄尔尼诺-南方涛动 (ENSO) 和印度洋偶极子 (IOD) 的可能影响及其机制. 研究发现, 坦桑尼亚OND降水在1997, 2006, 2011和2019年偏多 (1993, 1998, 2005和2016年偏少) . 降水偏多 (偏少) 年与气候态之间的差值场合成分析表明, 异常低层辐合 (辐散) 和上升 (下沉) 运动是降水偏多 (偏少) 的关键环流特征. 进一步分析发现, ENSO和IOD是调控坦桑尼亚OND降水年际变化的主要海洋系统. 厄尔尼诺事件和正位相IOD会引发印度洋低层东风异常并削弱其上空Walker环流, 从而导致坦桑尼亚水汽通量在低层辐合, 上升运动异常和降水增多. 相反, 拉尼娜事件和负位相IOD会引起相反的环流异常, 导致该地区降水减少. 通过偏相关分析和广义平衡反馈方法, 本文量化了ENSO和IOD对环流的独立贡献. 结果表明, 虽然IOD和ENSO均会影响Walker环流, 但IOD的作用强于ENSO. 这些发现为理解坦桑尼亚降水异常的海洋驱动因子及其机理路径提供了重要科学依据.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100614"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-02-20DOI: 10.1016/j.aosl.2025.100606
Yuhao Lin , Chunsong Lu , Yunying Li , Ru Zhou
Cloud type profoundly affects precipitation, but few studies have explored its impact on precipitation scale height. The authors calculated the ratio of the volume of each cloud type to the total cloud volume and partitioned the tropical region based on the dominant cloud types. Based on this, tropical regions were categorized into altocumulus control regions, stratocumulus control regions, deep convective cloud control regions, and transition regions. These regions exhibit unique characteristics: high precipitation scale heights and low surface precipitation rates in altocumulus control regions; low precipitation scale heights and low surface precipitation rates in stratocumulus control regions; and moderate precipitation scale heights with high surface precipitation rates in deep convective cloud regions. These features arise from differences in cloud characteristics, precipitation probability, and intensity, influenced by varying water vapor structures. In terms of physical mechanisms, altocumulus, stratocumulus, and deep convective cloud regions are characterized by total dryness, upper-level dryness with lower-level wetness, and total wetness, respectively. Upper-layer dryness leads to low cloud and precipitation structures, reducing the precipitation scale height, while lower-layer dryness increases it. Different humidity conditions in the upper and lower layers lead to variations in cloud type and volume distribution, ultimately affecting precipitation scale heights. This finding aids the mechanistic study of cloud precipitation physics in the tropics, providing valuable insights for developing numerical models and parameterizations.
{"title":"A new approach for identifying dominant cloud types and relationships between cloud types and precipitation vertical structure in tropical regions","authors":"Yuhao Lin , Chunsong Lu , Yunying Li , Ru Zhou","doi":"10.1016/j.aosl.2025.100606","DOIUrl":"10.1016/j.aosl.2025.100606","url":null,"abstract":"<div><div>Cloud type profoundly affects precipitation, but few studies have explored its impact on precipitation scale height. The authors calculated the ratio of the volume of each cloud type to the total cloud volume and partitioned the tropical region based on the dominant cloud types. Based on this, tropical regions were categorized into altocumulus control regions, stratocumulus control regions, deep convective cloud control regions, and transition regions. These regions exhibit unique characteristics: high precipitation scale heights and low surface precipitation rates in altocumulus control regions; low precipitation scale heights and low surface precipitation rates in stratocumulus control regions; and moderate precipitation scale heights with high surface precipitation rates in deep convective cloud regions. These features arise from differences in cloud characteristics, precipitation probability, and intensity, influenced by varying water vapor structures. In terms of physical mechanisms, altocumulus, stratocumulus, and deep convective cloud regions are characterized by total dryness, upper-level dryness with lower-level wetness, and total wetness, respectively. Upper-layer dryness leads to low cloud and precipitation structures, reducing the precipitation scale height, while lower-layer dryness increases it. Different humidity conditions in the upper and lower layers lead to variations in cloud type and volume distribution, ultimately affecting precipitation scale heights. This finding aids the mechanistic study of cloud precipitation physics in the tropics, providing valuable insights for developing numerical models and parameterizations.</div><div>摘要</div><div>云类型对降水有重要影响, 但其对降水尺度高度的作用研究尚少. 本研究通过计算各云类型体积占总云体积的比例, 将热带地区划分为高积云, 层积云, 深对流云控制区及过渡区. 高积云区降水尺度高度较高, 地表降水率较低; 层积云区降水尺度高度和地表降水率均较低; 深对流云区降水尺度高度适中, 地表降水率较高. 这些特征由云特性, 降水概率和强度的差异决定, 并受到水汽结构的影响. 高积云, 层积云和深对流云区分别表现为整体干燥, 上层干燥且下层湿润, 以及整体湿润的特征. 上层干燥降低降水尺度高度, 下层干燥则升高高度. 上下层湿度差异影响云类型分布和降水结构, 最终决定降水尺度高度. 本研究为云降水物理机制研究及数值模式开发提供了新视角.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100606"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-06-30DOI: 10.1016/j.aosl.2025.100672
Shenming Fu , Tingting Huang , Bo Wang , Xiao Li , Nan Zhang , Zhongcan Chen , Jingxue Wang , You Dong , Jianhua Sun
In mid-April 2025, northern and central-eastern China experienced a catastrophic compound disaster marked by Beaufort 8 or greater wind gusts affecting ∼3.5 × 106 km2, exposing ∼610 million residents to extreme conditions, with Typhoon-equivalent Beaufort 12 gusts battering Beijing’s Yanshan Mountains and Beaufort 14–15 winds devastating Inner Mongolia. This unprecedented event surpassed historical extremes at 64 weather stations, impacting 996 monitoring sites with winds exceeding the 99th percentile, including 478 stations recording historic top-three maxima. Concurrently, sandstorms engulfed ∼4.3 × 106 km2, reaching 18°N, while Hulunbuir faced a 1.5-m snowpack—a 30-year April record. Cascading infrastructure failures resulted in 1884 uprooted trees, approximately ¥16.6 million in urban damages (in Beijing), and the collapse of utility-scale photovoltaic systems across northern China and the Huang-Huai region, exacerbating the multi-faceted crisis. A brief analysis indicates the event was primarily driven by a vertically coupled cyclone system featuring a cold vortex at the middle and upper troposphere dynamically aligned with a lower-level cyclone/mesoscale vortex. The intense, deeply coupled cyclone system sustained the wind intensification primarily through its enhanced pressure gradient force and subsidence-induced downward transport of kinetic energy (KE) behind the cyclone’s core. Clarifying the controlling synoptic-scale weather systems and dominant physical mechanisms governing such extreme wind generation is critical for refining predictive models of these high-impact events while advancing the understanding of dynamic interactions within extreme wind regimes.
{"title":"The extreme windstorm of April 2025 in northern and central-eastern China: Historical ranking and synoptic origins","authors":"Shenming Fu , Tingting Huang , Bo Wang , Xiao Li , Nan Zhang , Zhongcan Chen , Jingxue Wang , You Dong , Jianhua Sun","doi":"10.1016/j.aosl.2025.100672","DOIUrl":"10.1016/j.aosl.2025.100672","url":null,"abstract":"<div><div>In mid-April 2025, northern and central-eastern China experienced a catastrophic compound disaster marked by Beaufort 8 or greater wind gusts affecting ∼3.5 × 10<sup>6</sup> km<sup>2</sup>, exposing ∼610 million residents to extreme conditions, with Typhoon-equivalent Beaufort 12 gusts battering Beijing’s Yanshan Mountains and Beaufort 14–15 winds devastating Inner Mongolia. This unprecedented event surpassed historical extremes at 64 weather stations, impacting 996 monitoring sites with winds exceeding the 99th percentile, including 478 stations recording historic top-three maxima. Concurrently, sandstorms engulfed ∼4.3 × 10<sup>6</sup> km<sup>2</sup>, reaching 18°N, while Hulunbuir faced a 1.5-m snowpack—a 30-year April record. Cascading infrastructure failures resulted in 1884 uprooted trees, approximately ¥16.6 million in urban damages (in Beijing), and the collapse of utility-scale photovoltaic systems across northern China and the Huang-Huai region, exacerbating the multi-faceted crisis. A brief analysis indicates the event was primarily driven by a vertically coupled cyclone system featuring a cold vortex at the middle and upper troposphere dynamically aligned with a lower-level cyclone/mesoscale vortex. The intense, deeply coupled cyclone system sustained the wind intensification primarily through its enhanced pressure gradient force and subsidence-induced downward transport of kinetic energy (KE) behind the cyclone’s core. Clarifying the controlling synoptic-scale weather systems and dominant physical mechanisms governing such extreme wind generation is critical for refining predictive models of these high-impact events while advancing the understanding of dynamic interactions within extreme wind regimes.</div><div>摘要</div><div>2025年4月中旬, 中国北部和中东部地区遭遇由8级以上阵风引发的复合型灾害, 影响范围约3.5 × 10⁶平方公里, 波及约6.1亿人口. 北京燕山山脉出现12级 (台风级) 阵风, 内蒙古局部地区风力达14–15级. 此次事件在64个气象站突破历史极值, 996个监测站点风速超过第99百分位 (478个站点创观测史前三极值) . 伴随沙尘暴影响范围达4.3 × 10⁶平方公里, 南扩至18°N; 呼伦贝尔出现1.5米积雪, 为30年来4月最深纪录. 灾害导致1884株树木倒伏, 北京城市设施损失约1660万元, 并造成华北, 黄淮地区光伏系统大面积损毁. 研究表明, 该事件由垂直耦合气旋系统驱动, 中高层冷涡与低层气旋/中尺度涡旋动力耦合, 通过增强气压梯度及下沉动能传输维持强风. 阐明此类极端风的天气系统及物理机制, 对改进预测模型及深化风场动力学认知具有重要意义.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100672"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-04-09DOI: 10.1016/j.aosl.2025.100619
Chang Liu, Lei Chen, Ke Li, Xipeng Jin, Xi Chen, Wenhao Qiao, Hong Liao
Renewable energy, especially solar power, is vital for mitigating global warming, while climate change also impacts solar photovoltaic potential (PVpot). This study analyzes historical (1985–2014) and future (2015–2100) climate effects on PVpot, and quantifies contributions from changed radiation, temperature, and wind speed. Historically, global PVpot increased by 0.42 ‰, with notable rises in eastern China (+7.1 ‰) and southern Europe (+3.5 ‰). By the end of the century, increased radiation-induced PVpot (+1.27 ‰) offsets temperature-induced PVpot loss (−0.54 ‰) under SSP1-2.6, yielding a net PVpot increase (+0.74 ‰). Under SSP2-4.5, the temperature-induced PVpot decline (−1.50 ‰) drives the final PVpot reduction (−1.15 ‰). Under SSP3-7.0 and SSP5-8.5, combined radiation-induced (−1.94 ‰ and −1.99 ‰) and temperature-induced PVpot changes (−2.67 ‰ and −3.41 ‰) result in significant PVpot declines (−4.57 ‰ and −5.31 ‰). Regional analysis reveals that eastern China (+0.7‰ to +8.6 ‰), southern Europe (+0.3 ‰ to +2.5 ‰), and Northwest South America (+0.6 ‰ to +2.1 ‰) retain positive changes in future PVpot across all climate scenarios, which may be due to reduced aerosols and cloud cover, suggesting these areas can remain suitable for photovoltaic installations despite climate changes. In contrast, temperature-driven PVpot declines over the Qinghai–Tibet Plateau (−9.1 ‰ to −4.3 ‰) and northern Africa (−9.3 ‰ to −4.9 ‰) under future high-emission scenarios indicate that these historically advantageous regions will become less suitable for solar energy deployment. The findings underscore that climate changes driven by sustainable development pathways will generate more PVpot in the future for better global warming mitigation.
{"title":"Historical and future climate changes impact global solar photovoltaic power potential: Role of key meteorological variables","authors":"Chang Liu, Lei Chen, Ke Li, Xipeng Jin, Xi Chen, Wenhao Qiao, Hong Liao","doi":"10.1016/j.aosl.2025.100619","DOIUrl":"10.1016/j.aosl.2025.100619","url":null,"abstract":"<div><div>Renewable energy, especially solar power, is vital for mitigating global warming, while climate change also impacts solar photovoltaic potential (PVpot). This study analyzes historical (1985–2014) and future (2015–2100) climate effects on PVpot, and quantifies contributions from changed radiation, temperature, and wind speed. Historically, global PVpot increased by 0.42 ‰, with notable rises in eastern China (+7.1 ‰) and southern Europe (+3.5 ‰). By the end of the century, increased radiation-induced PVpot (+1.27 ‰) offsets temperature-induced PVpot loss (−0.54 ‰) under SSP1-2.6, yielding a net PVpot increase (+0.74 ‰). Under SSP2-4.5, the temperature-induced PVpot decline (−1.50 ‰) drives the final PVpot reduction (−1.15 ‰). Under SSP3-7.0 and SSP5-8.5, combined radiation-induced (−1.94 ‰ and −1.99 ‰) and temperature-induced PVpot changes (−2.67 ‰ and −3.41 ‰) result in significant PVpot declines (−4.57 ‰ and −5.31 ‰). Regional analysis reveals that eastern China (+0.7‰ to +8.6 ‰), southern Europe (+0.3 ‰ to +2.5 ‰), and Northwest South America (+0.6 ‰ to +2.1 ‰) retain positive changes in future PVpot across all climate scenarios, which may be due to reduced aerosols and cloud cover, suggesting these areas can remain suitable for photovoltaic installations despite climate changes. In contrast, temperature-driven PVpot declines over the Qinghai–Tibet Plateau (−9.1 ‰ to −4.3 ‰) and northern Africa (−9.3 ‰ to −4.9 ‰) under future high-emission scenarios indicate that these historically advantageous regions will become less suitable for solar energy deployment. The findings underscore that climate changes driven by sustainable development pathways will generate more PVpot in the future for better global warming mitigation.</div><div>摘要</div><div>可再生能源, 特别是太阳能发电对于减缓全球变暖至关重要, 但气候变化会影响太阳能光伏潜力 (PVpot) . 本研究分析了历史 (1985–2014年) 和未来 (2015–2100年) 气候对PVpot的影响, 量化了辐射, 温度和风速的贡献. 从历史上看, 全球PVpot增加了0.42 ‰, 其中中国东部 (+7.1 ‰) 和南欧 (+3.5 ‰) 的增长显著. 到本世纪末, 在SSP1-2.6下, 辐射引起的PVpot增加 (+1.27 ‰) 抵消了温度引起的PVpot损失 (−0.54 ‰) , 从而PVpot增加 (+0.74 ‰). 在SSP2-4.5下, 温度引起的PVpot下降 (−1.50 ‰) 导致最终PVpot减少 (−1.15 ‰) . 在SSP3-7.0和SSP5-8.5中, 辐射引起的 (−1.94 ‰和−1.99 ‰) 和温度引起的PVpot变化 (−2.67 ‰和−3.41 ‰) 共同导致PVpot显著下降 (−4.57 ‰和−5.31 ‰) . 区域分析表明, 中国东部 (+0.7 ‰∼+8.6 ‰) , 南欧 (+0.3 ‰∼+2.5 ‰) 和南美洲西北部 (+0.6 ‰∼+2.1 ‰) 在所有气候情景下的PVpot都保持正变化, 这可能是由于气溶胶和云量减少, 这表明尽管未来气候变化, 这些地区仍然适合安装光伏设备. 相比之下, 在高排放情景下, 青藏高原 (−9.1 ‰∼−4.3 ‰) 和北非 (−9.3‰∼−4.9 ‰) 的光伏发电量因温度升高而下降, 这些历史上有利的地区将不再适合部署太阳能. 本研究结果强调, 可持续发展道路推动的气候变化将在未来产生更多的光伏发电量, 从而更好地减缓全球变暖.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100619"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-03-07DOI: 10.1016/j.aosl.2025.100613
Yi Zheng , Bo Sun , Wanling Li , Siyu Zhou , Jiarui Cai , Huixin Li , Shengping He
The discrepancy in the trends of the global zonal mean (GZM) intensity of the Hadley circulation (HCI) between reanalysis data and model simulations has been a problem for understanding the changes in HCI and the influence of external forcings. To understand the reason for this discrepancy, this study investigates the trends of intensity of regional HCI of the Northern Hemisphere over the eastern Pacific (EPA), western Pacific (WPA), Atlantic (ATL), Africa (AFR), the Indian Ocean (IDO), and residual area (RA), based on six reanalysis datasets and 13 CMIP6 models. In reanalysis data, the trends in regional HCI over EPA and ATL (WPA and AFR) contribute to (partially offset) the increasing trend in GZM HCI, while the trends in regional HCI over IDO are different in different reanalysis data. The CMIP6 models skillfully reproduce the trends in regional HCI over EPA, ATL, WPA, and AFR, but simulate notable decreasing trends in regional HCI over IDO, which is a key reason for the opposite trends in GZM HCI between reanalysis data and models. The discrepancy in IDO can be attributed to differences in the simulation of diabatic heating and zonal friction between reanalysis data and models. Optimal fingerprint analysis indicates that anthropogenic (ANT) and non-greenhouse gas (NOGHG) forcings are the dominant drivers of the HCI trends in the EPA and ATL regions. In the WPA (AFR) region, NOGHG (ANT) forcing serves as the primary driver. The findings contribute to improving the representation of regional HCI trends in models and improving the attribution of external forcings.
{"title":"Attribution of regional Hadley circulation intensity changes in the Northern Hemisphere","authors":"Yi Zheng , Bo Sun , Wanling Li , Siyu Zhou , Jiarui Cai , Huixin Li , Shengping He","doi":"10.1016/j.aosl.2025.100613","DOIUrl":"10.1016/j.aosl.2025.100613","url":null,"abstract":"<div><div>The discrepancy in the trends of the global zonal mean (GZM) intensity of the Hadley circulation (HCI) between reanalysis data and model simulations has been a problem for understanding the changes in HCI and the influence of external forcings. To understand the reason for this discrepancy, this study investigates the trends of intensity of regional HCI of the Northern Hemisphere over the eastern Pacific (EPA), western Pacific (WPA), Atlantic (ATL), Africa (AFR), the Indian Ocean (IDO), and residual area (RA), based on six reanalysis datasets and 13 CMIP6 models. In reanalysis data, the trends in regional HCI over EPA and ATL (WPA and AFR) contribute to (partially offset) the increasing trend in GZM HCI, while the trends in regional HCI over IDO are different in different reanalysis data. The CMIP6 models skillfully reproduce the trends in regional HCI over EPA, ATL, WPA, and AFR, but simulate notable decreasing trends in regional HCI over IDO, which is a key reason for the opposite trends in GZM HCI between reanalysis data and models. The discrepancy in IDO can be attributed to differences in the simulation of diabatic heating and zonal friction between reanalysis data and models. Optimal fingerprint analysis indicates that anthropogenic (ANT) and non-greenhouse gas (NOGHG) forcings are the dominant drivers of the HCI trends in the EPA and ATL regions. In the WPA (AFR) region, NOGHG (ANT) forcing serves as the primary driver. The findings contribute to improving the representation of regional HCI trends in models and improving the attribution of external forcings.</div><div>摘要</div><div>基于6套再分析资料和13个CMIP6模式, 研究发现模式能够较好地再现北半球东太平洋, 西太平洋, 大西洋和非洲的哈德来环流强度变化趋势. 但在印度洋区域, 再分析数据与模式模拟的趋势存在较大差异. 这一差异主要归因于模式与再分析数据在非绝热加热和纬向摩擦力模拟上的不同表现. 最优指纹法分析表明, 人为强迫和非温室气体强迫是北半球局地哈德来环流强度变化的主要驱动因素. 本研究揭示了人类活动对北半球不同区域哈德来环流变化的重要影响, 并阐明了再分析资料与CMIP6模式中北半球哈德来环流变化差异的原因.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100613"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-01-06DOI: 10.1016/j.aosl.2025.100590
Qiyang Liu , Anboyu Guo , Fengxue Qiao , Xinjian Ma , Yan-An Liu , Yong Huang , Rui Wang , Chunyan Sheng
Accurate short-term forecast of offshore wind fields is still challenging for numerical weather prediction models. Based on three years of 48-hour forecast data from the European Centre for Medium-Range Weather Forecasts Integrated Forecasting System global model (ECMWF-IFS) over 14 offshore weather stations along the coast of Shandong Province, this study introduces a multi-task learning (MTL) model (TabNet-MTL), which significantly improves the forecast bias of near-surface wind direction and speed simultaneously. TabNet-MTL adopts the feature engineering method, utilizes mean square error as the loss function, and employs the 5-fold cross validation method to ensure the generalization ability of the trained model. It demonstrates superior skills in wind field correction across different forecast lead times over all stations compared to its single-task version (TabNet-STL) and three other popular single-task learning models (Random Forest, LightGBM, and XGBoost). Results show that it significantly reduces root mean square error of the ECMWF-IFS wind speed forecast from 2.20 to 1.25 m s−1, and increases the forecast accuracy of wind direction from 50 % to 65 %. As an explainable deep learning model, the weather stations and long-term temporal statistics of near-surface wind speed are identified as the most influential variables for TabNet-MTL in constructing its feature engineering.
对于数值天气预报模式来说，海上风场的短期准确预报仍然是一个挑战。基于欧洲中期天气预报中心综合预报系统全球模式（ECMWF-IFS）在山东省沿海14个海上气象站3年的48小时预报数据，引入了TabNet-MTL模型，该模型显著改善了近地面风向和风速的预报偏差。TabNet-MTL采用特征工程方法，以均方误差作为损失函数，并采用5重交叉验证方法保证训练模型的泛化能力。与单任务版本（TabNet-STL）和其他三种流行的单任务学习模型（Random Forest， LightGBM和XGBoost）相比，它在所有站点不同预测提前期的风场校正方面表现出了卓越的技能。结果表明，该方法将ECMWF-IFS风速预报均方根误差从2.20 m s - 1显著降低到1.25 m s - 1，将风向预报精度从50%提高到65%。作为一种可解释的深度学习模型，气象站和近地面风速的长期时间统计数据是TabNet-MTL特征工程中影响最大的变量。摘要目前, 数值业务预报模式对沿海站点短期风场的准确预报仍存在挑战. 本研究基于欧洲中期天气预报中心ECMWF-IFS的高分辨率模式未来48小时的预报数据,构建适用于沿海风场订正的热动力特征,关键变量的短期和长期统计特征,引入多任务深度学习模型(TabNet-MTL)对山东省14个沿海气象站的风向和风速预报同时进行订正。相比于多个单任务学习模型(随机森林,LightGBM, XGBoost和TabNet-STL), TabNet-MTL模型具有显著的偏差订正优势,风速预报的均方根误差从2.20 s−1降低到1.25年代−1,风向预报准确率从50%提高到65%。此外,TabNet-MTL模型具有可解释性,特征重要性表明气象站点和近地面风速统计特征对风场订正的改善具有较大贡献。
{"title":"Skillful bias correction of offshore near-surface wind field forecasting based on a multi-task machine learning model","authors":"Qiyang Liu , Anboyu Guo , Fengxue Qiao , Xinjian Ma , Yan-An Liu , Yong Huang , Rui Wang , Chunyan Sheng","doi":"10.1016/j.aosl.2025.100590","DOIUrl":"10.1016/j.aosl.2025.100590","url":null,"abstract":"<div><div>Accurate short-term forecast of offshore wind fields is still challenging for numerical weather prediction models. Based on three years of 48-hour forecast data from the European Centre for Medium-Range Weather Forecasts Integrated Forecasting System global model (ECMWF-IFS) over 14 offshore weather stations along the coast of Shandong Province, this study introduces a multi-task learning (MTL) model (TabNet-MTL), which significantly improves the forecast bias of near-surface wind direction and speed simultaneously. TabNet-MTL adopts the feature engineering method, utilizes mean square error as the loss function, and employs the 5-fold cross validation method to ensure the generalization ability of the trained model. It demonstrates superior skills in wind field correction across different forecast lead times over all stations compared to its single-task version (TabNet-STL) and three other popular single-task learning models (Random Forest, LightGBM, and XGBoost). Results show that it significantly reduces root mean square error of the ECMWF-IFS wind speed forecast from 2.20 to 1.25 m s<sup>−1</sup>, and increases the forecast accuracy of wind direction from 50 % to 65 %. As an explainable deep learning model, the weather stations and long-term temporal statistics of near-surface wind speed are identified as the most influential variables for TabNet-MTL in constructing its feature engineering.</div><div>摘要</div><div>目前, 数值业务预报模式对沿海站点短期风场的准确预报仍存在挑战. 本研究基于欧洲中期天气预报中心ECMWF-IFS的高分辨率模式未来48小时的预报数据, 构建适用于沿海风场订正的热动力特征, 关键变量的短期和长期统计特征, 引入多任务深度学习模型 (TabNet-MTL) 对山东省14个沿海气象站的风向和风速预报同时进行订正. 相比于多个单任务学习模型 (随机森林, LightGBM, XGBoost和TabNet-STL) , TabNet-MTL模型具有显著的偏差订正优势, 风速预报的均方根误差从2.20 m s<sup>−1</sup>降低到 1.25 m s<sup>−1</sup>, 风向预报准确率从50 %提高到65 %.此外, TabNet-MTL模型具有可解释性, 特征重要性表明气象站点和近地面风速统计特征对风场订正的改善具有较大贡献.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100590"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2024-12-09DOI: 10.1016/j.aosl.2024.100585
Yao Ha , Haixia Dai , Shuai Song , Yaming Zhao , Wei Lu
The Meiyu in the Yangtze–Huaihe River basin (YHRB) in 2023 was featured by delayed onset and retreat, a shorter duration, and below-normal Meiyu precipitation. The relatively weak cold air invading southward from the mid-to-high latitudes in late May–early June contributed to the delayed onset of Meiyu season, and the persistent rainfall caused by Typhoon “Talim” and Super Typhoon “Doksuri” led to the delayed retreat. The westward-shifted and intensified western Pacific subtropical high (WPSH), coupled with the eastward-shifted and strengthened south Asian high (SAH), as well as the Eurasian mid-to-high latitude circulation featuring “two troughs–one ridge”, resulting in the below-average Meiyu precipitation with the heaviest rainfall primally in eastern YHRB. Further analysis indicates that the 2023 Meiyu was influenced by the combined effects of the decaying La Niña, warm sea surface temperature (SST) anomalies in the North Pacific west wind drift area, and less than normal snow cover over the Tibetan Plateau. Warmer than normal SST in the western Pacific warm pool and the North Pacific westerly drift region favored the narrow meridional circulation at middle latitudes and WPSH, whereas the strengthened SAH and East Asian summer monsoon were impacted by persistently reduced snow cover over the northeastern Tibetan Plateau.
{"title":"Characteristics and possible causes of the Meiyu over the Yangtze–Huaihe River Basin in 2023","authors":"Yao Ha , Haixia Dai , Shuai Song , Yaming Zhao , Wei Lu","doi":"10.1016/j.aosl.2024.100585","DOIUrl":"10.1016/j.aosl.2024.100585","url":null,"abstract":"<div><div>The Meiyu in the Yangtze–Huaihe River basin (YHRB) in 2023 was featured by delayed onset and retreat, a shorter duration, and below-normal Meiyu precipitation. The relatively weak cold air invading southward from the mid-to-high latitudes in late May–early June contributed to the delayed onset of Meiyu season, and the persistent rainfall caused by Typhoon “Talim” and Super Typhoon “Doksuri” led to the delayed retreat. The westward-shifted and intensified western Pacific subtropical high (WPSH), coupled with the eastward-shifted and strengthened south Asian high (SAH), as well as the Eurasian mid-to-high latitude circulation featuring “two troughs–one ridge”, resulting in the below-average Meiyu precipitation with the heaviest rainfall primally in eastern YHRB. Further analysis indicates that the 2023 Meiyu was influenced by the combined effects of the decaying La Niña, warm sea surface temperature (SST) anomalies in the North Pacific west wind drift area, and less than normal snow cover over the Tibetan Plateau. Warmer than normal SST in the western Pacific warm pool and the North Pacific westerly drift region favored the narrow meridional circulation at middle latitudes and WPSH, whereas the strengthened SAH and East Asian summer monsoon were impacted by persistently reduced snow cover over the northeastern Tibetan Plateau.</div><div>摘要</div><div>2023年中国江淮流域入梅和出梅日期均偏晚, 梅雨量整体偏少. 本文研究发现, 5月末6月初中高纬冷空气偏弱是入梅偏晚的原因, 台风“泰利”和强台风“杜苏芮”引起的持续性降水导致了出梅偏晚. 中低纬地区偏西偏强的西太平洋副热带高压和偏东偏强的南亚高压叠置, 配合欧亚中高纬 “两槽一脊”环流型, 使得江淮流域梅雨量偏少, 且降水集中在江淮流域东部. 进一步分析表明, 2023年梅雨期中国受La Niña 衰减位相的影响, 西太平洋暖池和北太平洋西风漂流区的暖海温异常导致中纬度环流经向性偏弱, 西太平洋副热带高压偏西, 偏强. 而南亚高压和东亚夏季风异常主要受到青藏高原东北部积雪持续异常偏少的影响.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100585"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Three Gorges Region (TGR) of the Yangtze River basin exhibited warm and dry climatic characteristics in 2024. The annual mean temperature in the TGR was 18.6 °C, which was 1.2 °C above normal and marked the highest level since 1961. All four seasons were warmer than normal, with spring and autumn both recording their highest temperatures since 1961. Additionally, the TGR recorded 57.2 high-temperature days in 2024, reaching a historic high since 1961 and exceeding the previous record set in 2022 by 2.4 days. Annual rainfall was 11.2 % below normal, with spring, summer, and autumn all being drier than normal. However, the number of heavy rain days was slightly higher than normal. The annual mean wind speed in the TGR ranked as the second-highest since 1961, only slightly lower than in 2022. The annual mean relative humidity was below normal and the number of fog days across large areas of the TGR decreased compared to 2023. In 2024, the TGR experienced extreme high-temperature events characterized by exceptional intensity and prolonged duration, accompanied by generally severe meteorological drought conditions. During the year, the TGR also experienced frequent and intense cooling events, an early onset of heavy rainfall (including severe convective weather), and exceptionally extreme rainstorm events.
{"title":"State of the climate over the Three Gorges Region of the Yangtze River basin in 2024","authors":"Hongling Zeng, Xianyan Chen, Yundi Jiang, Xukai Zou, Tong Cui, Qiang Zhang, Linhai Sun","doi":"10.1016/j.aosl.2025.100664","DOIUrl":"10.1016/j.aosl.2025.100664","url":null,"abstract":"<div><div>The Three Gorges Region (TGR) of the Yangtze River basin exhibited warm and dry climatic characteristics in 2024. The annual mean temperature in the TGR was 18.6 °C, which was 1.2 °C above normal and marked the highest level since 1961. All four seasons were warmer than normal, with spring and autumn both recording their highest temperatures since 1961. Additionally, the TGR recorded 57.2 high-temperature days in 2024, reaching a historic high since 1961 and exceeding the previous record set in 2022 by 2.4 days. Annual rainfall was 11.2 % below normal, with spring, summer, and autumn all being drier than normal. However, the number of heavy rain days was slightly higher than normal. The annual mean wind speed in the TGR ranked as the second-highest since 1961, only slightly lower than in 2022. The annual mean relative humidity was below normal and the number of fog days across large areas of the TGR decreased compared to 2023. In 2024, the TGR experienced extreme high-temperature events characterized by exceptional intensity and prolonged duration, accompanied by generally severe meteorological drought conditions. During the year, the TGR also experienced frequent and intense cooling events, an early onset of heavy rainfall (including severe convective weather), and exceptionally extreme rainstorm events.</div><div>摘要</div><div>2024年长江三峡地区的气候呈暖干特征, 年平均气温创下新的纪录, 达到18.6 °C, 较常年偏高1.2 °C. 四季气温均偏高, 其中春秋季平均气温均为1961年以来历史同期最高. 高温日数为57.2天, 也为1961年以来最多. 年降水量较常年偏少11.2 %, 春, 夏, 秋三季降水均偏少, 但暴雨日数较常年略偏多. 年平均风速为1961年以来第二大, 仅略低于2022年. 年平均相对湿度偏小, 大部地区雾日数较2023年有所减少. 2024年, 三峡地区经历极端高温事件, 高温强度强, 持续时间长, 气象干旱总体偏重; 强降温频次多, 强度强; 强降水 (强对流) 天气过程偏早, 暴雨极端性强.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100664"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The South China Sea winter monsoon (SCSWM), an integral component of the East Asian winter monsoon, connects extratropical and tropical regions. Utilizing ERA5 reanalysis and PAMIP simulations, the relationship between Arctic sea ice and the SCSWM is investigated. The authors reveal that its strongest relationship with Arctic sea ice occurs in the North Pacific sector, i.e., the Sea of Okhotsk and western Bering Sea. This link persists throughout the cold season, peaks when sea ice precedes the SCSWM by one month, and is independent of ENSO. North Pacific sea-ice loss weakens the meridional temperature gradient (MTG) and vertical wind shear in midlatitudes, reducing baroclinic eddy formation. Given the reduced zonal wind according to the thermal wind relation, the reduced wave activity flux in the upper troposphere must be balanced by equatorward wind based on the quasi-geostrophic momentum equation. This generates an anomalous meridional overturning circulation with descent and low-level divergence around 30°N, which intensifies the divergent component of the SCSWM. The divergent northerly anomalies also lead to cold advection and subtropical cooling. The enhanced MTG due to the subtropical cooling and weakened MTG due to high-latitude warming closely tied to reduced North Pacific sea ice displace the westerly jet southward, creating cyclonic shears over the North Pacific and intensifying the rotational component of the SCSWM. These findings establish North Pacific sea ice as a non-ENSO driver of the SCSWM, holding substantial implications for the predictability of the SCSWM.
{"title":"A non-ENSO driver of the South China Sea winter monsoon: North Pacific sea ice","authors":"Chang Kong , Xiaodan Chen , Zhiping Wen , Yuanyuan Guo","doi":"10.1016/j.aosl.2025.100593","DOIUrl":"10.1016/j.aosl.2025.100593","url":null,"abstract":"<div><div>The South China Sea winter monsoon (SCSWM), an integral component of the East Asian winter monsoon, connects extratropical and tropical regions. Utilizing ERA5 reanalysis and PAMIP simulations, the relationship between Arctic sea ice and the SCSWM is investigated. The authors reveal that its strongest relationship with Arctic sea ice occurs in the North Pacific sector, i.e., the Sea of Okhotsk and western Bering Sea. This link persists throughout the cold season, peaks when sea ice precedes the SCSWM by one month, and is independent of ENSO. North Pacific sea-ice loss weakens the meridional temperature gradient (MTG) and vertical wind shear in midlatitudes, reducing baroclinic eddy formation. Given the reduced zonal wind according to the thermal wind relation, the reduced wave activity flux in the upper troposphere must be balanced by equatorward wind based on the quasi-geostrophic momentum equation. This generates an anomalous meridional overturning circulation with descent and low-level divergence around 30°N, which intensifies the divergent component of the SCSWM. The divergent northerly anomalies also lead to cold advection and subtropical cooling. The enhanced MTG due to the subtropical cooling and weakened MTG due to high-latitude warming closely tied to reduced North Pacific sea ice displace the westerly jet southward, creating cyclonic shears over the North Pacific and intensifying the rotational component of the SCSWM. These findings establish North Pacific sea ice as a non-ENSO driver of the SCSWM, holding substantial implications for the predictability of the SCSWM.</div><div>摘要</div><div>南海冬季风作为东亚冬季风系统的重要组成部分, 在热带与热带外地区的相互作用中发挥着重要作用. 使用大气再分析数据和环流模式试验, 本研究探讨了北极海冰与南海冬季风之间的关系. 研究表明, 影响南海冬季风的北极海冰关键区在鄂霍次克海. 以鄂霍次克海和西白令海为主的北太平洋海冰减少, 可通过调节垂直经向环流和副热带急流, 显著增强南海冬季风的辐散分量和旋转分量. 这一联系不受ENSO影响, 对南海冬季风的预测以及理解北极与热带之间的联系具有重要的科学意义.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100593"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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