Atmospheric and Oceanic Science Letters最新文献

{"title":"Evaluating vector winds over eastern China in 2022 predicted by the CMA-MESO model and ECMWF forecast","authors":"Fang Huang ,&nbsp;Mingjian Zeng ,&nbsp;Zhongfeng Xu ,&nbsp;Boni Wang ,&nbsp;Ming Sun ,&nbsp;Hangcheng Ge ,&nbsp;Shoukang Wu","doi":"10.1016/j.aosl.2024.100559","DOIUrl":"10.1016/j.aosl.2024.100559","url":null,"abstract":"<div><div>Vector winds play a crucial role in weather and climate, as well as the effective utilization of wind energy resources. However, limited research has been conducted on treating the wind field as a vector field in the evaluation of numerical weather prediction models. In this study, the authors treat vector winds as a whole by employing a vector field evaluation method, and evaluate the mesoscale model of the China Meteorological Administration (CMA-MESO) and ECMWF forecast, with reference to ERA5 reanalysis, in terms of multiple aspects of vector winds over eastern China in 2022. The results show that the ECMWF forecast is superior to CMA-MESO in predicting the spatial distribution and intensity of 10-m vector winds. Both models overestimate the wind speed in East China, and CMA-MESO overestimates the wind speed to a greater extent. The forecasting skill of the vector wind field in both models decreases with increasing lead time. The forecasting skill of CMA-MESO fluctuates more and decreases faster than that of the ECMWF forecast. There is a significant negative correlation between the model vector wind forecasting skill and terrain height. This study provides a scientific evaluation of the local application of vector wind forecasts of the CMA-MESO model and ECMWF forecast.</div><div>摘要</div><div>本文利用矢量场评估VFE方法, 从矢量场角度系统性评估CMA-MESO模式与ECMWF模式对2022年华东地区10 m高度矢量风场的预报技巧. 结果表明, ECMWF模式对矢量风场空间分布与风场强度的预报均优于CMA-MESO模式. CMA-MESO模式明显高估了矢量风场的强度. 模式预报技巧随着预报时效的延长而下降, 其中以CMA-MESO模式的预报技巧波动更大, 衰减更迅速. 本研究将为CMA-MESO模式与ECMWF模式风场预报产品的本地化应用, 提供一个科学的评估依据.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 4","pages":"Article 100559"},"PeriodicalIF":2.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169722","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":"Fluctuations in the relationship between the Silk Road Pattern and the summer North Atlantic Oscillation","authors":"Yong Liu ,&nbsp;Zhencai Du","doi":"10.1016/j.aosl.2024.100558","DOIUrl":"10.1016/j.aosl.2024.100558","url":null,"abstract":"<div><div>This study investigated the fluctuations in the relationship between the Silk Road Pattern (SRP) and the boreal summer North Atlantic Oscillation (SNAO). The results indicated that the SRP–SNAO relationship was relatively weak during 1958–2022, which was primarily due to fluctuations, particularly the reversal in their relationship since the late 1990s. Using wavelet coherence analysis, the authors identified a strong SRP–SNAO linkage on a 4–8-yr timescale, in particular during the mid-1970s to the early/mid-1990s. This strong linkage is mainly attributable to the intensification and eastward movement of the southern part of the SNAO around the mid/late 1970s, which favored the strong connection between the SNAO and the SRP. Additionally, the interdecadal changes of the atmospheric circulations over the North Atlantic and Eurasia around the mid/late 1970s that resembled the circulation anomalies related to the strong SRP–SNAO linkage, may also have provided a favorable background for the strong connection between the two teleconnections. These findings on the fluctuations in the SRP–SNAO linkage may offer important implications for understanding the impact of the SNAO on the SRP and the variability of the SRP.</div><div>摘要</div><div>本文利用近60年大气再分析数据, 研究了丝绸之路型遥相关 (Silk Road Pattern, SRP) 与夏季北大西洋涛动 (North Atlantic Oscillation, SNAO) 关系的不稳定性及其可能成因. 结果表明, 近60年来, SRP与SNAO的关系具有明显的不稳定性. 两者关系在1970s中期至1990s中期显著增强, 特别在4-8年时间尺度上. 两者关系的增强主要与1970s中后期以来SNAO南部中心增强, 位置东移有关. 同时, 北大西洋和欧亚区域夏季大气环流在1970s末的年代际异常也为两者之间关系的增强提供了有利的气候背景.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 4","pages":"Article 100558"},"PeriodicalIF":2.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169721","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":"Employment of an Arctic sea-ice data assimilation scheme in the coupled climate system model FGOALS-f3-L and its preliminary results","authors":"Yuyang Guo ,&nbsp;Yongqiang Yu ,&nbsp;Jiping Liu","doi":"10.1016/j.aosl.2024.100553","DOIUrl":"10.1016/j.aosl.2024.100553","url":null,"abstract":"<div><div>Arctic sea ice is an important component of the global climate system and has experienced rapid changes during in the past few decades, the prediction of which is a significant application for climate models. In this study, a Localized Error Subspace Transform Kalman Filter is employed in a coupled climate system model (the Flexible Global Ocean–Atmosphere–Land System Model, version f3-L (FGOALS-f3-L)) to assimilate sea-ice concentration (SIC) and sea-ice thickness (SIT) data for melting-season ice predictions. The scheme is applied through the following steps: (1) initialization for generating initial ensembles; (2) analysis for assimilating observed data; (3) adoption for dividing ice states into five thickness categories; (4) forecast for evolving the model; (5) resampling for updating model uncertainties. Several experiments were conducted to examine its results and impacts. Compared with the control experiment, the continuous assimilation experiments (CTNs) indicate assimilations improve model SICs and SITs persistently and generate realistic initials. Assimilating SIC+SIT data better corrects overestimated model SITs spatially than when only assimilating SIC data. The continuous assimilation restart experiments indicate the initials from the CTNs correct the overestimated marginal SICs and overall SITs remarkably well, as well as the cold biases in the oceanic and atmospheric models. The initials with SIC+SIT assimilated show more reasonable spatial improvements. Nevertheless, the SICs in the central Arctic undergo abnormal summer reductions, which is probably because overestimated SITs are reduced in the initials but the strong seasonal cycle (summer melting) biases are unchanged. Therefore, since systematic biases are complicated in a coupled system, for FGOALS-f3-L to make better ice predictions, oceanic and atmospheric assimilations are expected required.</div><div>摘要</div><div>当前, 快速变化的北极海冰对全球气候有重要影响, 海冰的预报是气候模式的重要应用方向之一. 本研究基于PDAF同化框架, 使用LESTKF方法将北极海冰密集度 (SIC) 和厚度 (SIT) 观测数据同化到气候系统模式FGOALS-f3-L中开展融化季节的海冰预测. 同化的引入共分为集合初始化, 同化分析, 分析场引入, 模式预报, 集合重采样等五个步骤. 试验表明, 连续同化可以持续改进模式模拟的SIC和SIT并生成接近真实的初始场, 同时同化SIC和SIT比只同化SIC能更好地纠正SIT的空间偏差. 利用连续同化生成的初始场进行预报, 能够显著减少海冰边缘的SIC多偏差, 整体的SIT厚偏差以及海洋和大气中的冷偏差, 使用同化了SIC和SIT的初始场能带来更合理的空间改进. 但受模式中海冰季节循环偏强的影响, 预报的夏季海冰会出现偏少, 这表明在耦合系统中准确预报海冰还需纳入海洋和大气同化.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 4","pages":"Article 100553"},"PeriodicalIF":2.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169720","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":"Variation in the permafrost active layer over the Tibetan Plateau during 1980–2020","authors":"","doi":"10.1016/j.aosl.2024.100536","DOIUrl":"10.1016/j.aosl.2024.100536","url":null,"abstract":"<div><p>The active layer, acting as an intermediary of water and heat exchange between permafrost and atmosphere, greatly influences biogeochemical cycles in permafrost areas and is notably sensitive to climate fluctuations. Utilizing the Chinese Meteorological Forcing Dataset to drive the Community Land Model, version 5.0, this study simulates the spatial and temporal characteristics of active layer thickness (ALT) on the Tibetan Plateau (TP) from 1980 to 2020. Results show that the ALT, primarily observed in the central and western parts of the TP where there are insufficient station observations, exhibits significant interdecadal changes after 2000. The average thickness on the TP decreases from 2.54 m during 1980–1999 to 2.28 m during 2000–2020. This change is mainly observed in the western permafrost region, displaying a sharp regional inconsistency compared to the eastern region. A persistent increasing trend of ALT is found in the eastern permafrost region, rather than an interdecadal change. The aforementioned changes in ALT are closely tied to the variations in the surrounding atmospheric environment, particularly air temperature. Additionally, the area of the active layer on the TP displays a profound interdecadal change around 2000, arising from the permafrost thawing and forming. It consistently decreases before 2000 but barely changes after 2000. The regional variation in the permafrost active layer over the TP revealed in this study indicates a complex response of the contemporary climate under global warming.</p><p>摘要</p><p>活动层是多年冻土和大气之间的缓冲层, 对气候波动十分敏感, 其冻融变化对多年冻土区的地球生物化学循环有较大影响. 本研究利用高分辨率气象数据集CMFD和陆面过程模式CLM5.0模拟分析了青藏高原1980–2020年活动层的变化. 结果表明: 青藏高原的活动层厚度在2000年后有显著的年代际变化, 青藏高原整体活动层厚度由1980–1999的2.54 m减少到2000–2020年的2.28 m. 这种变化主要发生在西部的多年冻土区, 与东部相比存在明显的区域差异. 在东部, 多年冻土区的活动层厚度呈持续增加趋势, 而不是年代际变化. 此外, 活动层面积在2000年也发生了年代际突变, 之前持续下降, 但之后几乎没有变化. 本文还发现青藏高原多年冻土活动层的区域变化受到气温和降水等环境因子的显著影响, 这反映了其在全球变暖背景下对气候变化的复杂响应.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100536"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000850/pdfft?md5=5bdbe6b3d2873446dbdfcebd7b8938c7&pid=1-s2.0-S1674283424000850-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141392826","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":"Future changes in precipitation and water availability over the Tibetan Plateau projected by CMIP6 models constrained by climate sensitivity","authors":"Hui Qiu ,&nbsp;Tianjun Zhou ,&nbsp;Liwei Zou ,&nbsp;Jie Jiang ,&nbsp;Xiaolong Chen ,&nbsp;Shuai Hu","doi":"10.1016/j.aosl.2024.100537","DOIUrl":"10.1016/j.aosl.2024.100537","url":null,"abstract":"<div><p>Precipitation projections over the Tibetan Plateau (TP) show diversity among existing studies, partly due to model uncertainty. How to develop a reliable projection remains inconclusive. Here, based on the IPCC AR6–assessed likely range of equilibrium climate sensitivity (ECS) and the climatological precipitation performance, the authors constrain the CMIP6 (phase 6 of the Coupled Model Intercomparison Project) model projection of summer precipitation and water availability over the TP. The best estimates of precipitation changes are 0.24, 0.25, and 0.45 mm d⁻¹ (5.9 %, 6.1 %, and 11.2 %) under the Shared Socioeconomic Pathway (SSP) scenarios of SSP1–2.6, SSP2–4.5, and SSP5–8.5 from 2050–2099 relative to 1965–2014, respectively. The corresponding constrained projections of water availability measured by precipitation minus evaporation (P–E) are 0.10, 0.09, and 0.22 mm d⁻¹ (5.7 %, 4.9 %, and 13.2 %), respectively. The increase of precipitation and P–E projected by the high-ECS models, whose ECS values are higher than the upper limit of the likely range, are about 1.7 times larger than those estimated by constrained projections. Spatially, there is a larger increase in precipitation and P–E over the eastern TP, while the western part shows a relatively weak difference in precipitation and a drier trend in P–E. The wetter TP projected by the high-ECS models resulted from both an approximately 1.2–1.4 times stronger hydrological sensitivity and additional warming of 0.6 °C–1.2 °C under all three scenarios during 2050–2099. This study emphasizes that selecting climate models with climate sensitivity within the likely range is crucial to reducing the uncertainty in the projection of TP precipitation and water availability changes.</p><p>摘要</p><p>青藏高原是气候变化敏感区, 可靠的气候预估对气候变化应对至关重要. 青藏高原夏季降水变化的预估结果在CMIP6气候模式间存在较大的不确定性, 原因部分地和这些模式对温室气体强迫的敏感度不同有关. 作者在对CMIP6模式性能进行评估基础上, 选择了具有较高气候态降水模拟技巧的模式用于预估研究, 并根据IPCC AR6估算的平衡态气候敏感度 (ECS) 的可能性范围, 对青藏高原夏季降水的中远期 (2050–2099) 变化进行约束. 结果表明, 在SSP1–2.6, SSP2–4.5 和 SSP5–8.5情景下, 青藏高原夏季降水将分别增多0.24, 0.25 和 0.45 mm d⁻¹ (5.9 %, 6.1 %, 和 11.2 %), 水资源可用性 (P–E) 将分别增加0.10, 0.09和0.22 mm d⁻¹(5.7 %, 4.9 % 和13.2 %) . 与约束预估相比, 高ECS模式预估的水文敏感度约为约束后的1.2–1.4倍, 升温幅度偏高0.6 °C–1.2 °C, 这二者共同导致高ECS模式预估的高原降水增幅约为约束预估的1.7倍. 本文指出气候敏感度是影响未来青藏高原水资源预估不确定性的重要来源, 同时基于IPCC AR6对ECS的最佳估算, 给出了高原夏季降水和水资源的最佳预估结果.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100537"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000862/pdfft?md5=68c7bec658cb012bffbe4f08b8df1040&pid=1-s2.0-S1674283424000862-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161546","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":"A study on the simulation of carbon and water fluxes of Dangxiong alpine meadow and its response to climate change","authors":"","doi":"10.1016/j.aosl.2024.100507","DOIUrl":"10.1016/j.aosl.2024.100507","url":null,"abstract":"<div><p>The alpine meadow ecosystem accounts for 27 % of the total area of the Tibetan Plateau and is also one of the most important vegetation types. The Dangxiong alpine meadow ecosystem, located in the south-central part of the Tibetan Plateau, is a typical example. To understand the carbon and water fluxes, water use efficiency (WUE), and their responses to future climate change for the alpine meadow ecosystem in the Dangxiong area, two parameter estimation methods, the Model-independent Parameter Estimation (PEST) and the Dynamic Dimensions Search (DDS), were used to optimize the Biome-BGC model. Then, the gross primary productivity (GPP) and evapotranspiration (ET) were simulated. The results show that the DDS parameter calibration method has a better performance. The annual GPP and ET show an increasing trend, while the WUE shows a decreasing trend. Meanwhile, ET and GPP reach their peaks in July and August, respectively, and WUE shows a “dual-peak” pattern, reaching peaks in May and November. Furthermore, according to the simulation results for the next nearly 100 years, the ensemble average GPP and ET exhibit a significant increasing trend, and the growth rate under the SSP5–8.5 scenario is greater than that under the SSP2–4.5 scenario. WUE shows an increasing trend under the SSP2–4.5 scenario and a significant increasing trend under the SSP5–8.5 scenario. This study has important scientific significance for carbon and water cycle prediction and vegetation ecological protection on the Tibetan Plateau.</p><p>摘要</p><p>全球气候变化对青藏高原生态系统产生了深远影响, 暖湿化背景下青藏高原植被碳, 水通量变化趋势值得关注. 高寒草甸是青藏高原最主要的植被类型之一, 为理解青藏高原当雄地区高寒草甸生态系统碳, 水通量, 水分利用效率及其对未来气候变化的响应, 本研究利用PEST和DDS两种参数率定方法优化Biome-BGC模型, 进而模拟2000–2019年当雄站的总初级生产力 (GPP) 和蒸散量 (ET) . 研究结果表明: DDS参数率定方法具有更优的性能. GPP和ET在研究时段内呈上升趋势, 而水分利用效率 (WUE) 则呈下降趋势. 同时, ET和GPP分别在7月和8月达到峰值, 而WUE则呈“双峰”变化, 分别于5月和11月达到峰值. 此外, 未来近百年的模拟表明GPP和ET的集合平均结果呈显著增加趋势, 其中在SSP5–8.5情景下的增速大于SSP2–4.5情景. WUE在SSP2–4.5情景下呈增加趋势, 而在SSP5–8.5情景下呈显著增加趋势. 本研究结果可为青藏高原碳, 水循环预测研究和植被生态保护的应用研究提供参考和借鉴.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100507"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000564/pdfft?md5=321f26220b000716c9b88ec2f566bdec&pid=1-s2.0-S1674283424000564-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140774115","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":"Climate state of the Three Gorges Region in the Yangtze River basin in 2022–2023","authors":"Tong Cui,&nbsp;Xianyan Chen,&nbsp;Xukai Zou,&nbsp;Linhai Sun,&nbsp;Qiang Zhang,&nbsp;Hongling Zeng","doi":"10.1016/j.aosl.2024.100540","DOIUrl":"10.1016/j.aosl.2024.100540","url":null,"abstract":"<div><p>Based on daily observation data of the Three Gorges Region (TGR) of the Yangtze River basin and global reanalysis data, the climate characteristics, climate events, and meteorological disasters of the TGR in 2022 and 2023 were analyzed. For the TGR, the average annual temperature for 2022 and 2023 was 0.8 °C and 0.4 °C higher than normal, respectively, making them the two warmest years in the past decade. In 2022, the TGR experienced its warmest summer on record. The average air temperature was 2.4 °C higher than the average, and there were 24.8 days of above-average high temperature days during summer. Rainfall in the TGR varied significantly between 2022 and 2023. Annual rainfall was 18.4 % below normal and drier than normal in most parts of the region. In contrast, the precipitation in 2023 was considerably higher than the long-term average, and above normal for almost the entire year. The average wind speed exhibited minimal variation between the two years. However, the number of foggy days and relative humidity increased in 2023 compared to 2022. In 2022–2023, the TGR mainly experienced meteorological disasters such as extreme high temperatures, regional heavy rain and flooding, overcast rain, and inverted spring chill. Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.</p><p>摘要</p><p>基于长江三峡地区观测资料和全球再分析资料, 分析了该地区 2022–2023年气候特征, 酸雨状况以及主要天气气候事件. 2022 年和2023年三峡地区平均气温分别较常年偏高0.8 °C和0.4 °C, 是近十年来最暖的两年, 特别是2022年夏季出现破记录极端高温; 2022年三峡地区降水量较常年偏少18.4 %, 2023年降水量转为偏多15.3 %. 在这两年中该地区主要出现了极端高温, 区域性暴雨洪涝, 连阴雨和倒春寒等气候事件. 分析表明, 西太平洋副热带高压和南亚高压协同异常是2022年夏季极端高温维持的两个重要因素.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100540"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000898/pdfft?md5=a56c614fe781f3779330a724ec56d0ae&pid=1-s2.0-S1674283424000898-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141842819","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":"State of China's climate in 2023","authors":"Linhai Sun,&nbsp;Xiaying Zhu,&nbsp;Wei Li,&nbsp;Wanxiu Ai,&nbsp;Xianyan Chen,&nbsp;Yundi Jiang,&nbsp;Ling Wang,&nbsp;Xukai Zou,&nbsp;Shanshan Zhao,&nbsp;Hongling Zeng,&nbsp;Hailing Zhong","doi":"10.1016/j.aosl.2024.100519","DOIUrl":"10.1016/j.aosl.2024.100519","url":null,"abstract":"<div><p>China witnessed a warm and dry climate in 2023. The annual surface air temperature reached a new high of 10.71°C, with the hottest autumn and the second hottest summer since 1961. Meanwhile, the annual precipitation was the second lowest since 2012, at 615.0 mm. Precipitation was less than normal from winter to summer, but more in autumn. Consistent with the annual condition, precipitation in the flood season from May to September was also the second lowest since 2012, which was 4.3% less than normal, with the anomalies in the central and eastern parts of China being higher in central areas and lower in the north and south. On the contrary, the West China Autumn Rain brought much more rainfall than normal, with an earlier start and later end. Although there was less annual precipitation in 2023, China suffered seriously from heavy precipitation events and floods. In particular, from the end of July to the beginning of August, a rare, extremely strong rainstorm caused by Typhoon Dussuri hit Beijing, Tianjin, and Hebei, causing an abrupt alteration from drought to flood conditions in North China. By contrast, Southwest China experienced continuous drought from the previous autumn to current spring. In early summer, North China and the Huanghuai region experienced the strongest high-temperature process since 1961. Nevertheless, there were more cold-air processes than normal impacting China, with the most severe of the year occurring in mid-January. Unexpectedly, in spring, there were more sand and dust occurrences in northern China.</p><p>摘要</p><p>2023年, 我国气候暖干特征明显, 全国平均气温10.71°C, 为1951年以来最暖; 全国平均降水量615.0 mm, 较常年偏少3.9%, 为2012年以来第二少. 汛期 (5–9月), 全国平均降水量为2012年以来第二少, 中东部降水总体呈“中间多南北少”的分布. 2023年, 我国区域性气象干旱多发, 西南地区遭遇冬春连旱; 春季北方沙尘天气过程偏多; 夏季前期, 华北和黄淮遭受1961年以来最强高温过程; 7月底至8月初, 受台风杜苏芮影响, 京津冀地区发生历史罕见极端强降雨过程, 华北地区出现“旱涝急转”; 华西秋雨开始早, 结束晚, 雨量多.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100519"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000680/pdfft?md5=33e16e8e8906bc4a86f1fe93d95642b9&pid=1-s2.0-S1674283424000680-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162281","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":"Isolated deep convections over the Tibetan Plateau in the rainy season during 2001–2020","authors":"","doi":"10.1016/j.aosl.2024.100489","DOIUrl":"10.1016/j.aosl.2024.100489","url":null,"abstract":"<div><p>The Tibetan Plateau (TP) is a prevalent region for convection systems due to its unique thermodynamic forcing. This study investigated isolated deep convections (IDCs), which have a smaller spatial and temporal size than mesoscale convective systems (MCSs), over the TP in the rainy season (June–September) during 2001–2020. The authors used satellite precipitation and brightness temperature observations from the Global Precipitation Measurement mission. Results show that IDCs mainly concentrate over the southern TP. The IDC number per rainy season decreases from around 140 over the southern TP to around 10 over the northern TP, with an average 54.2. The initiation time of IDCs exhibits an obvious diurnal cycle, with the peak at 1400–1500 LST and the valley at 0900–1000 LST. Most IDCs last less than five hours and more than half appear for only one hour. IDCs generally have a cold cloud area of 7422.9 km², containing a precipitation area of approximately 65%. The larger the IDC, the larger the fraction of intense precipitation it contains. IDCs contribute approximately 20%–30% to total precipitation and approximately 30%–40% to extreme precipitation over the TP, with a larger percentage in July and August than in June and September. In terms of spatial distribution, IDCs contribute more to both total precipitation and extreme precipitation over the TP compared to the surrounding plain regions. IDCs over the TP account for a larger fraction than MCSs, indicating the important role of IDCs over the region.</p><p>摘要</p><p>本文利用卫星观测资料, 研究了2001–2020年雨季 (6–9月) 青藏高原上孤立深对流 (Isolated deep convections, IDCs) 的气候特征. IDCs定义为比中尺度对流系统 (Mesoscale convective systems, MCSs) 时空尺度小的对流. 结果显示, 每年雨季青藏高原上平均的IDC数量为54.2个, 主要分布在高原的南部. IDCs的初始时刻呈现明显的日循环, 在下午14–15时为峰值, 在上午9–10时为谷值. 大部分IDCs持续时间在5小时以内, 超过一半的IDCs仅持续1小时. IDCs的冷云平均面积约为7422.9km², 其中包含65%的降水面积. IDC面积越大, 包含的强降水范围也越大. IDCs对青藏高原总降水的贡献约为20%–30%, 对极端降水贡献约为30%–40%, 在7月和8月的占比大于6月和9月. 在空间分布方面, 青藏高原上IDCs对总降水和极端降水的贡献大于周围平原地区. 青藏高原上IDCs对降水的贡献大于MCSs, 表明IDCs在该地区起着重要作用.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100489"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000382/pdfft?md5=308d88abdcdef39b723facf7c55f9df7&pid=1-s2.0-S1674283424000382-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140399858","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":"Insights from the Second Tibetan Plateau Scientific Expedition: Unveiling the westerly–monsoon synergy and hydroclimate changes","authors":"Chaofan Li ,&nbsp;Yaoming Ma ,&nbsp;Tianjun Zhou ,&nbsp;Riyu Lu","doi":"10.1016/j.aosl.2024.100541","DOIUrl":"10.1016/j.aosl.2024.100541","url":null,"abstract":"","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100541"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000904/pdfft?md5=f373c695dc0c6e2313e5a7149f1da2c9&pid=1-s2.0-S1674283424000904-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161548","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}