Atmospheric and Oceanic Science Letters最新文献

{"title":"A new approach for identifying dominant cloud types and relationships between cloud types and precipitation vertical structure in tropical regions","authors":"Yuhao Lin ,&nbsp;Chunsong Lu ,&nbsp;Yunying Li ,&nbsp;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":"2025-02-20","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}

{"title":"Impacts of El Niño–Southern Oscillation on global fire PM2.5 during 2000–2023","authors":"Yonghang Hu,&nbsp;Xu Yue,&nbsp;Chenguang Tian","doi":"10.1016/j.aosl.2025.100597","DOIUrl":"10.1016/j.aosl.2025.100597","url":null,"abstract":"<div><div>The El Niño–Southern Oscillation (ENSO) is a key driver of global climate variability, profoundly influencing regional fire activities and associated pollutant emissions. This study investigates the impacts of ENSO on global fire emissions and fire-induced PM_2.5 concentrations in 2000–2023. During El Niño events, global fire emissions increase by 5.9 %–20.0 % with regional hotspots in Indonesia, North America, and Australia, driven by anomalous warming and rainfall deficits. In contrast, La Niña events result in a 3.2 %–9.9 % reduction in global fire emissions, with regional variability depending on the fire inventories used. In response, fire-induced PM_2.5 concentrations increase substantially during El Niño, rising by 27.5 %–71.0 % in Indonesia, 49.2 %–116.5 % in North America, and 17.5 %–42.6 % in Australia. Conversely, La Niña events lead to decreases of 26.6 %–52.5 %, 19.4 %–37.3 %, 14.5 %–24.4 % in these regions, respectively. These findings highlight the critical role of ENSO in shaping fire emissions and air pollution from regional to global scales, providing valuable insights for mitigating the impacts of climatic extremes on air quality.</div><div>摘要</div><div>厄尔尼诺-南方涛动 (ENSO) 是全球气候变化的主要驱动因素, 对区域火灾活动及其相关污染物排放有深远影响. 本研究分析了2000–2023年期间ENSO对全球火灾排放及火灾引起的PM_2.5浓度的影响. 在厄尔尼诺事件期间, 由于异常增温和降水不足, 全球火灾排放增加5.9 %−20.0 %, 其中印度尼西亚, 北美和澳大利亚为火排放增幅最显著地区. 相比之下, 拉尼娜事件期间全球火灾排放减少3.2 %−9.9 %, 具体变化取决于所使用的火灾排放清单.在此背景下, 火灾引起的PM_2.5浓度在厄尔尼诺事件期间显著增加, 印度尼西亚增加27.5 %−71.0 %, 北美增加49.2 %−116.5 %, 澳大利亚增加17.5 %−42.6 %; 而在拉尼娜事件期间, 这些地区的PM_2.5浓度分别减少26.6 %−52.5 %, 19.4 %−37.3 %和14.5 %−24.4 %. 研究结果表明, ENSO从区域到全球尺度上深刻影响着火排放和空气污染物浓度, 相关结论为减缓极端气候事件对空气质量的影响提供了重要的科学依据.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 3","pages":"Article 100597"},"PeriodicalIF":2.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868403","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}

{"title":"The evolving distribution of humidity conditional on temperature and implications for compound heat extremes across China in a warming world","authors":"Caixia Liang ,&nbsp;Jiacan Yuan","doi":"10.1016/j.aosl.2025.100596","DOIUrl":"10.1016/j.aosl.2025.100596","url":null,"abstract":"<div><div>The likelihood of extreme heat occurrence is continuously increasing with global warming. Under high temperatures, humidity may exacerbate the heat impact on humanity. As atmospheric humidity depends on moisture availability and is constrained by air temperature, it is important to project the changes in the distribution of atmospheric humidity conditional on air temperature as the climate continuously warms. Here, a non-crossing quantile smoothing spline is employed to build quantile regression models emulating conditional distributions of dew point (a measure of humidity) on local temperature evolving with escalating global mean surface temperature. By applying these models to 297 weather stations in seven regions in China, the study analyzes historical trends of humid-heat and dry-hot days, and projects their changes under global warming of 2.0°C and 4.5°C. In response to global warming, rising trends of humid-heat extremes, while weakening trends of dry-hot extremes, are observed at most stations in Northeast China. Additionally, results indicate an increasing trend in dry-hot extremes at numerous stations across central China, but a rise in humid-heat extremes over Northwest China and coastal regions. These trends found in the current climate state are projected to intensify under 2.0°C and 4.5°C warming, possibly influenced by the heterogeneous variations in precipitation, soil moisture, and water vapor fluxes. Requiring much lower computational resources than coupled climate models, these quantile regression models can further project compound humidity and temperature extremes in response to different levels of global warming, potentially informing the risk management of compound humid-heat extremes on a local scale.</div><div>摘要</div><div>本研究利用非交叉分位数平滑样条, 对中国七个气候分区的297个气象站分别建立了分位数回归模型, 模拟露点温度基于局地温度的条件概率密度分布对全球变暖的响应, 并预测了这些分布分别在2.0°C和4.5°C温升情景下的变化. 结果表明, (1) 这些分布对全球变暖的响应存在较大的区域异质性: 东北地区, 西北地区与沿海地区大多数站点呈现出极端湿热事件增加的趋势; 而中国中部地区的多个站点呈现出极端干热事件增加的趋势. (2) 这些趋势预计在2.0°C和4.5°C的温升情景下将进一步加剧.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100596"},"PeriodicalIF":3.2,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903210","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}

{"title":"Mechanistic study of a downhill merging and enhancement of convection in Beijing","authors":"Xinyu Zhao ,&nbsp;Lingkun Ran ,&nbsp;Shunwu Zhou ,&nbsp;Xinyong Shen ,&nbsp;Mingxuan Chen ,&nbsp;Yanli Chu","doi":"10.1016/j.aosl.2025.100595","DOIUrl":"10.1016/j.aosl.2025.100595","url":null,"abstract":"<div><div>Numerical simulation of the merging of a thunderstorm cluster from the mountain area near Beijing and a thunderstorm over the adjacent plains on 23 August 2021, along with a diagnosis and analysis of the cold pool and vertical motion, reveals the following: (1) The thunderstorm cluster in the mountain area moved slowly westward, weakening during its descent, whereas the thunderstorm cluster in the urban area moved rapidly eastward and intensified. Eventually, the two thunderstorm clusters encountered each other at the foot of the mountain and organized into a linear convective system. (2) Prior to merging, the thunderstorm cluster in the mountain area was blocked by warm advection to the east, causing the system to slow down, the cold pool to weaken, and the convergence and ascent associated with the cold pool outflow to diminish. In contrast, the thunderstorm cluster over the adjacent plains was driven by cold advection to the west, accelerating the system's movement, strengthening the cold pool, and enhancing the convergence and ascent driven by the cold pool outflow. After the thunderstorm clusters merged, the convergence of the northwesterly and southeasterly winds, as well as precipitation, led to the rapid accumulation of cold air, strengthening the cold pool and its upward development, which acted similarly to a terrain feature, further enhancing convergence and ascent. (3) The vertical motion reveals that before merging, the thunderstorm cluster in the mountain area was dominated by negative buoyancy at lower levels, which suppressed the development of ascent, whereas the thunderstorm cluster over the adjacent plains was driven by positive disturbances in the vertical pressure gradient force, which increased ascent. After the merging, the positive disturbances in the vertical pressure gradient force dominated below 2 km, and as the vertical motion increased, the positive buoyancy gradually became the dominant driver, further strengthening the ascent. The analysis suggests that the positive potential temperature disturbance and the southeasterly or southerly winds over the adjacent plains had opposing effects on the two approaching thunderstorm clusters, with the thunderstorm cluster over the adjacent plains taking the lead during the merging process.</div><div>摘要</div><div>以往针对北京平原雷暴群和下山雷暴群合并过程的研究相对较少, 利用WRF模拟数据对2021年8月23日一次此类对流活动过程分析发现： (1) 雷暴群前侧风场和热力条件的差异, 使得山区雷暴群移动和冷池发展受阻, 而平原雷暴群则相反, 最终在山脚处合并, 增强后的冷池起到类似地形作用, 增强辐合和上升运动； (2) 合并前, 山区雷暴群低层负热力浮力抑制上升运动发展, 平原雷暴群低层正扰动垂直气压梯度力加速上升运动, 合并后, 正扰动垂直气压梯度力 (2 km以下) 和正热力浮力 (2 km以上) 共同驱动上升运动发展. 本文主要对冷池和垂直运动分析, 以期为北京地区的临近预报提供一些有用的科学参考.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 6","pages":"Article 100595"},"PeriodicalIF":3.2,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903209","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}

{"title":"A non-ENSO driver of the South China Sea winter monsoon: North Pacific sea ice","authors":"Chang Kong ,&nbsp;Xiaodan Chen ,&nbsp;Zhiping Wen ,&nbsp;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":"2025-01-15","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}

{"title":"Subseasonal impact of extreme Tibetan Plateau snow cover on the local atmosphere in summer","authors":"Yuanyan Xu,&nbsp;Wenkai Li","doi":"10.1016/j.aosl.2025.100591","DOIUrl":"10.1016/j.aosl.2025.100591","url":null,"abstract":"<div><div>Due to the high elevation and cold climate of the Tibetan Plateau, the western region retains extensive snow cover during the summer, which can exhibit rapid variability over the course of just a few days. This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover (TPSC) events on a subseasonal timescale during summer. The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period. Nevertheless, local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover. Specifically, an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo, resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally. This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures. The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa. These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.</div><div>摘要</div><div>青藏高原海拔高, 气候寒冷, 其西部地区在夏季仍有积雪覆盖, 且积雪变化可能在数日内迅速发生. 本文通过数值试验研究了大气对夏季青藏高原极端积雪事件的次季节响应. 结果表明, 尽管极端积雪事件对非局地大气环流及温度的影响有限, 但局地地表能量收支和大气温度对积雪增加表现出快速的冷却响应. 具体而言, 青藏高原西部积雪增加会导致地表反照率迅速上升, 从而减少地表能量输入. 此变化引发了局地地表至350 hPa高度的非绝热加热率的负异常响应, 进而导致地表及上空大气温度下降. 气温响应主要局限于青藏高原西部, 并且从地表垂直延伸至约350 hPa高度. 上述夏季青藏高原极端积雪事件及其大气影响发生在两周时间内.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100591"},"PeriodicalIF":2.3,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144696477","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}

{"title":"Skillful bias correction of offshore near-surface wind field forecasting based on a multi-task machine learning model","authors":"Qiyang Liu ,&nbsp;Anboyu Guo ,&nbsp;Fengxue Qiao ,&nbsp;Xinjian Ma ,&nbsp;Yan-An Liu ,&nbsp;Yong Huang ,&nbsp;Rui Wang ,&nbsp;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⁻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.</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⁻¹降低到 1.25 m s⁻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.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 5","pages":"Article 100590"},"PeriodicalIF":2.3,"publicationDate":"2025-01-06","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}

{"title":"Optimizing the key parameter to accelerate the recovery of AMOC under a rapid increase of greenhouse gas forcing","authors":"Haolan Ren ,&nbsp;Fei Zheng ,&nbsp;Tingwei Cao ,&nbsp;Qiang Wang","doi":"10.1016/j.aosl.2024.100509","DOIUrl":"10.1016/j.aosl.2024.100509","url":null,"abstract":"<div><div>Atlantic Meridional Overturning Circulation (AMOC) plays a central role in long-term climate variations through its heat and freshwater transports, which can collapse under a rapid increase of greenhouse gas forcing in climate models. Previous studies have suggested that the deviation of model parameters is one of the major factors in inducing inaccurate AMOC simulations. In this work, with a low-resolution earth system model, the authors try to explore whether a reasonable adjustment of the key model parameter can help to re-establish the AMOC after its collapse. Through a new optimization strategy, the extra freshwater flux (FWF) parameter is determined to be the dominant one affecting the AMOC's variability. The traditional ensemble optimal interpolation (EnOI) data assimilation and new machine learning methods are adopted to optimize the FWF parameter in an abrupt 4×CO₂ forcing experiment to improve the adaptability of model parameters and accelerate the recovery of AMOC. The results show that, under an abrupt 4×CO₂ forcing in millennial simulations, the AMOC will first collapse and then re-establish by the default FWF parameter slowly. However, during the parameter adjustment process, the saltier and colder sea water over the North Atlantic region are the dominant factors in usefully improving the adaptability of the FWF parameter and accelerating the recovery of AMOC, according to their physical relationship with FWF on the interdecadal timescale.</div><div>摘要</div><div>大西洋经向翻转环流 (Atlantic Meridional Overturning Circulation, AMOC) 通过其经向的热量和水团输送, 在气候变化中起着关键作用. 然而, 气候模式模拟未来AMOC在温室气体强迫下的变化存在较大不确定性. 模式参数的不确定性是导致AMOC产生不确定性的主要因素之一. 因此, 本文采用简化的海气耦合模式首先探寻出模式中AMOC的最敏感参数为淡水通量系数 (Freshwater Flux, FWF), 再基于集合最优插值 (Ensemble Optimal Interpolation, EnOI) 探讨通过参数优化减小温室气体强迫下AMOC模拟不确定性的可行方案. 理想试验揭示了, 北大西洋海表温度和海表盐度在温室气体强迫下的增量可以有效地优化FWF, 进而使得AMOC相比默认参数能快速收敛, 减小其在未来气候预估中的不确定性.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 1","pages":"Article 100509"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140758227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interannual variability of boreal summer intraseasonal oscillation over the northwestern Pacific influenced by the Pacific Meridional Mode","authors":"Haoyu Zhou,&nbsp;Pang-Chi Hsu,&nbsp;Lin Chen,&nbsp;Yitian Qian","doi":"10.1016/j.aosl.2024.100492","DOIUrl":"10.1016/j.aosl.2024.100492","url":null,"abstract":"<div><div>During the boreal summer, intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions: the central-western equatorial Pacific (5°S–5°N, 150°E–150°W) and the subtropical Northwestern Pacific (10°–20°N, 130°E–175°W). The former is well-documented and considered to be influenced by the ENSO, while the latter has received comparatively less attention and is likely influenced by the Pacific Meridional Mode (PMM), as suggested by partial correlation analysis results. To elucidate the physical processes responsible for the enhanced (weakened) intraseasonal convection over the subtropical northwestern Pacific during warm (cold) PMM years, the authors employed a moisture budget analysis. The findings reveal that during warm PMM years, there is an increase in summer-mean moisture over the subtropical northwestern Pacific. This increase interacts with intensified vertical motion perturbations in the region, leading to greater vertical moisture advection in the lower troposphere and consequently resulting in convective instability. Such a process is pivotal in amplifying intraseasonal convection anomalies. The observational findings were further verified by model experiments forced by PMM-like sea surface temperature patterns.</div><div>摘要</div><div>在北半球夏季, 西北太平洋地区的季节内振荡在两个主要区域呈现出显著的年际变率: 一个区域是赤道太平洋中西部 (5°S–5°N, 150°E–150°W), 另一区域为副热带西北太平洋 (10°–20°N, 130°E–175°W). 通过偏相关分析, 揭示了前者受到厄尔尼诺–南方涛动 (ENSO) 的影响, 而后者与太平洋经向模态 (PMM) 有关. 利用水汽方程诊断, 探讨了在PMM暖 (冷) 年期间, 副热带西北太平洋季节内对流活动增强 (减弱) 的物理过程. 结果表明, 在PMM暖年, 副热带西北太平洋地区的季节平均水汽增加与季节内垂直扰动的增强相互作用, 导致了对流层低层水汽垂直输送的增加, 进而引发对流不稳定性的增强, 促使季节内对流活动增强. 这一发现在以PMM海温为驱动的全球环流模式试验中也得到了验证.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 1","pages":"Article 100492"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140399719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Satellite remote sensing reveals overwhelming recovery of forest from disturbances in Asia","authors":"Yiying Zhu ,&nbsp;Hesong Wang ,&nbsp;Anzhi Zhang","doi":"10.1016/j.aosl.2024.100511","DOIUrl":"10.1016/j.aosl.2024.100511","url":null,"abstract":"<div><div>Forest ecosystems play key roles in mitigating human-induced climate change through enhanced carbon uptake; however, frequently occurring climate extremes and human activities have considerably threatened the stability of forests. At the same time, detailed accounts of disturbances and forest responses are not yet well quantified in Asia. This study employed the Breaks For Additive Seasonal and Trend method—an abrupt-change detection method—to analyze the Enhanced Vegetation Index time series in East Asia, South Asia, and Southeast Asia. This approach allowed us to detect forest disturbance and quantify the resilience after disturbance. Results showed that 20 % of forests experienced disturbance with an increasing trend from 2000 to 2022, and Southeast Asian countries were more severely affected by disturbances. Specifically, 95 % of forests had robust resilience and could recover from disturbance within a few decades. The resilience of forests suffering from greater magnitude of disturbance tended to be stronger than forests with lower disturbance magnitude. In summary, this study investigated the resilience of forests across the low and middle latitudes of Asia over the past two decades. The authors found that most forests exhibited good resilience after disturbance and about two-thirds had recovered to a better state in 2022. The findings of this study underscore the complex relationship between disturbance and resilience, contributing to comprehension of forest resilience through satellite remote sensing.</div><div>摘要</div><div>目前对于亚洲森林在应对气候变化和人类活动干扰方面的研究相对较少. 本研究利用BFAST突变检测方法, 分析了东亚, 南亚和东南亚的增强植被指数 (EVI) 长时间序列中检测到的森林扰动和恢复情况. 结果显示, 2000年至2022年期间, 约20%的森林经历了扰动, 且受到扰动的森林面积呈增加趋势, 东南亚国家受扰动的影响更为严重. 在扰动事件发生后, 95%的森林具有较好的恢复能力, 能够在受到扰动后的一段时间后恢复过来, 其中约有三分之二的森林在2022年时已经恢复到了较扰动前更好的状态.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 1","pages":"Article 100511"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140764371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}