Atmospheric and Oceanic Science Letters最新文献

{"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":"Projected changes in extreme snowfall events over the Tibetan Plateau based on a set of RCM simulations","authors":"","doi":"10.1016/j.aosl.2023.100446","DOIUrl":"10.1016/j.aosl.2023.100446","url":null,"abstract":"<div><p>Extreme snowfall events over the Tibetan Plateau (TP) cause considerable damage to local society and natural ecosystems. In this study, the authors investigate the projected changes in such events over the TP and its surrounding areas based on an ensemble of a set of 21st century climate change projections using a regional climate model, RegCM4. The model is driven by five CMIP5 global climate models at a grid spacing of 25 km, under the RCP4.5 and RCP8.5 pathways. Four modified ETCCDI extreme indices—namely, SNOWTOT, S1mm, S10mm, and Sx5day—are employed to characterize the extreme snowfall events. RegCM4 generally reproduces the spatial distribution of the indices over the region, although with a tendency of overestimation. For the projected changes, a general decrease in SNOWTOT is found over most of the TP, with greater magnitude and better cross-simulation agreement over the eastern part. All the simulations project an overall decrease in S1mm, ranging from a 25% decrease in the west and to a 50% decrease in the east of the TP. Both S10mm and Sx5day are projected to decrease over the eastern part and increase over the central and western parts of the TP. Notably, S10mm shows a marked increase (more than double) with high cross-simulation agreement over the central TP. Significant increases in all four indices are found over the Tarim and Qaidam basins, and northwestern China north of the TP. The projected changes show topographic dependence over the TP in the latitudinal direction, and tend to decrease/increase in low-/high-altitude areas.</p><p>摘要</p><p>基于RegCM4区域气候模式的气候变化预估试验数据, 开展了青藏高原及其周边地区极端降雪事件的未来变化研究. 结果表明, 总降雪量在高原大部分地区呈减少趋势, 降雪日数在高原也将明显减少, 尤其是在东部. 大雪日数和五日最大降雪量在高原东部将减少, 而在中部和西部明显增加. 在高原周边的塔里木和柴达木盆地及中国西北地区, 极端降雪事件同样增加显著. 极端降雪事件在高原上呈现出东西方向上的地形依赖性, 在低/高海拔地区呈减少/增加趋势.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100446"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283423001459/pdfft?md5=0f9d88b01fcd624760a099c0666f3808&pid=1-s2.0-S1674283423001459-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139302808","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}

{"title":"Research progress on the water vapor channel within the Yarlung Zsangbo Grand Canyon, China","authors":"","doi":"10.1016/j.aosl.2024.100462","DOIUrl":"10.1016/j.aosl.2024.100462","url":null,"abstract":"<div><p>The Second Tibetan Plateau Scientific Expedition and Research Program tasked a research team with the “Investigation of the water vapor channel of the Yarlung Zsangbo Grand Canyon (INVC)” in the southeastern Tibetan Plateau (TP). This paper summarizes the scientific achievements obtained from the data collected by the INVC observation network and highlights the progress in investigating the development of heavy rainfall events associated with water vapor changes. The rain gauge network of the INVC can represent the impacts of the Yarlung Zsangbo Grand Canyon (YGC) topography on precipitation at the hourly scale. The microphysical characteristics of the precipitation in the YGC are different than those in the lowland area. The GPM-IMERG (Integrated Multi-satellitE Retrievals for Global Precipitation Measurement) satellite precipitation data for the YGC region should be calibrated before they are used. The meridional water vapor flux through the YGC is more important than the zonal flux for the precipitation over the southeastern TP. The decreased precipitation around the YGC region is partly due to the decreased meridional water vapor flux passing through the YGC. High-resolution numerical models can benefit precipitation forecasting in this region by using a combination of specific schemes that capture the valley wind and water vapor flux along the valley floor.</p><p>摘要</p><p>第二次青藏高原科学考察研究在青藏高原东南部组建了雅鲁藏布大峡谷水汽通道科学考察分队, 本文主要总结了该科考分队近几年开展的观测研究以及利用该分队建立的观测网收集的观测数据所取得的科学成果, 重点介绍了与大峡谷水汽输送相关的强降雨过程的研究进展; 研究主要发现科考分队在大峡谷建立的雨量筒观测网可以代表该地区地形对小时降水量的空间影响; 藏东南降水的微物理特征与低海拔地区有明显差异; GPM卫星降水数据在大峡谷地区存在干偏差的问题, 使用前需进行校准; 穿越大峡谷的经向水汽输送对青藏高原东南部的降水有重要影响, 大峡谷周边区域降水量的减少可能是由于穿越大峡谷经向水汽通量的减少造成; 使用特定云降水方案的高分辨率数值模型可以较好的捕捉大峡谷内的风场和水汽输送时, 该模型能对该地区夜间强降水做出准确预报.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100462"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000102/pdfft?md5=eafc877f376f6713edcfbb4d393eee74&pid=1-s2.0-S1674283424000102-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139455693","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":"Variation in the surface heat flux on the north and south slopes of Mount Qomolangma","authors":"Yonghao Jiang ,&nbsp;Maoshan Li ,&nbsp;Yuchen Liu ,&nbsp;Ting Wang ,&nbsp;Pei Xu ,&nbsp;Yaoming Ma ,&nbsp;Fanglin Sun","doi":"10.1016/j.aosl.2024.100513","DOIUrl":"10.1016/j.aosl.2024.100513","url":null,"abstract":"<div><p>The distinctive conditions present on the north and south slopes of Mount Qomolangma, along with the intricate variations in the underlying surfaces, result in notable variations in the surface energy flux patterns of the two slopes. In this paper, data from TESEBS (Topographical Enhanced Surface Energy Balance System), remote sensing data from eight cloud-free scenarios, and observational data from nine stations are utilized to examine the fluctuations in the surface heat flux on both slopes. The inclusion of MCD43A3 satellite data enhances the surface albedo, contributing to more accurate simulation outcomes. The model results are validated using observational data. The RMSEs of the net radiation, ground heat, sensible heat, and latent heat flux are 40.73, 17.09, 33.26, and 30.91 W m⁻², respectively. The net radiation flux is greater on the south slope and exhibits a rapid decline from summer to autumn. Due to the influence of the monsoon, on the north slope, the maximum sensible heat flux occurs in the pre-monsoon period in summer and the maximum latent heat flux occurs during the monsoon. The south slope experiences the highest latent heat flux in summer. The dominant flux on the north slope is sensible heat, while it is latent heat on the south slope. The seasonal variations in the ground heat flux are more pronounced on the south slope than on the north slope. Except in summer, the ground heat flux on the north slope surpasses that on the south slope.</p><p>摘要</p><p>珠穆朗玛峰南北坡独特的地形条件和复杂的下垫面, 导致了南北坡地表通量分布的显著差异. 本文利用地形增强地表能量平衡模式 (Topographical Enhanced Surface Energy Balance System (TESEBS)), 遥感数据和站点观测数据, 对季风和非季风期南北坡的地表热通量变化进行了研究. 首先, 把MCD43A3卫星数据加入TESEBS, 改进了地表反照率, 使模拟结果更准确. 受季风影响, 北坡季风期感热通量最大值出现在季风前期, 潜热通量最大值出现在季风期. 南坡季风期潜热通量最大. 全年北坡以感热交换为主, 南坡以潜热交换为主. 土壤热通量的季节变化在南坡比北坡更明显.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100513"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S167428342400062X/pdfft?md5=55246a9b274532fc324f6ce1bb0a7c75&pid=1-s2.0-S167428342400062X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161545","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":"Interdecadal variability of summer precipitation in the Three River Source Region: Influences of SST and zonal shifts of the East Asian subtropical westerly jet","authors":"Yumeng Liu ,&nbsp;Xianhong Meng ,&nbsp;Lin Zhao ,&nbsp;S.-Y. Simon Wang ,&nbsp;Lixia Zhang ,&nbsp;Zhaoguo Li ,&nbsp;Chan Wang ,&nbsp;Yingying An","doi":"10.1016/j.aosl.2024.100538","DOIUrl":"10.1016/j.aosl.2024.100538","url":null,"abstract":"<div><p>Summer precipitation in the Three Rivers Source Region (TRSR) of China is vital for the headwaters of the Yellow, Yangtze, and Lancang rivers and exhibits significant interdecadal variability. This study investigates the influence of the East Asian westerly jet (EAWJ) on TRSR rainfall. A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index (JZPI) of the EAWJ from 1961 to 2019 (<em>R</em> = 0.619, <em>p</em> &lt; 0.01). During periods when a positive JZPI indicates a westward shift in the EAWJ, enhanced water vapor anomalies, warmer air, and low-level convergence anomalies contribute to increased TRSR summer precipitation. Using empirical orthogonal function and regression analyses, this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection (AEA) from the North Atlantic (NA). The interdecadal variability between the NA and central tropical Pacific (CTP) significantly affects TRSR precipitation. This influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ, and another south of 45°N. Moreover, the NA–CTP Opposite Phase Index (OPI), which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP, is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ.</p><p>摘要</p><p>本研究探讨了年代际东亚西风急流的纬向移动对黄河, 长江和澜沧江源头—三江源区夏季降水的影响. 研究发现, 在1961–2019年间, 三江源区夏季降水量与急流纬向位置指数 (JZPI) 在年代际尺度上存在强正相关 (R=0.619, p&lt;0.01) . 当JZPI呈正值, 也就是东亚西风急流向西移动时, 增强的水汽, 温暖的气流和低层辐合异常有助于三江源区夏季降水增加. 北大西洋与中太平洋之间的年代际变化对三江源区的降水有着显著的影响, 主要以北大西洋–欧亚遥相关 (AEA) 方式, 通过沿东亚西风急流向东延伸的罗斯贝波列, 以及45°N以南的另一波列来影响三江源区的降水. 进一步分析发现, 北大西洋与中太平洋反向相位指数 (OPI) 作为一个关键因素, 可量化北大西洋与中太平洋之间夏季平均海表温度的差异, 调控该遥相关的强度并影响急流的纬向位置.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 5","pages":"Article 100538"},"PeriodicalIF":2.3,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283424000874/pdfft?md5=910f4a8135a00150d333cde44ed9dc4c&pid=1-s2.0-S1674283424000874-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162280","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":"Projection of extreme climate change in the Asian arid region and the Tibetan Plateau in the early and middle 21st century based on NEX-GDDP-CMIP6","authors":"Yankun Sun ,&nbsp;Rui Zhu ,&nbsp;Tao Wang","doi":"10.1016/j.aosl.2024.100534","DOIUrl":"10.1016/j.aosl.2024.100534","url":null,"abstract":"<div><div>In the context of global warming, it is anticipated that both the intensity and the frequency of future global extreme high precipitation (EHP) and extreme high temperature (EHT) events will increase. To evaluate the future extreme climate changes in the Asian arid region and Tibetan Plateau, this study applied the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP-CMIP6) to assess the changes in EHP (Rx5d and R95pTOT) and EHT (TX90p and TXx) under different emission scenarios in the 21st century. Findings suggest that both the frequency and the intensity of the extreme indices will increase, exhibiting accelerated growth under higher emission scenarios, particularly under the SSP5-8.5 emission scenario. It is suggested that the growth of EHT and EHP in the early subperiod of the 21st century (2026–2045) will be relatively moderate, with small differences between different emission scenarios. However, by the middle subperiod of the 21st century (2041–2060), the differences between different emission scenarios will become larger than the 2035s and the growth will become more intense. In western central Asia, TX90p, TXx, Rx5d, and R95pTOT increase by 9.7%–14.2% (13.3%–24.7%), 1.3°C–1.7°C (1.6°C–2.7°C), 6.5%–8.9% (8.2%–8.8%), and 18.1%–27.0% (25.6%–30.0%) by the early (middle) subperiod; in eastern central Asia, TX90p, TXx, Rx5d, and R95pTOT increase 8.1%–12.0% (11.3%–21.1%), 1.4°C–1.8°C (1.9°C–2.9°C), 7.4%–9.7% (10.4%–13.8%), and 20.2%–29.3% (32.0%–40.8%) by the early (middle) subperiod; and over the Tibetan Plateau, TX90p, TXx, Rx5d, and R95pTOT increase 12.5%–17.4% (17.0%–31.0%), 1.2°C–1.5°C (1.6°C–2.5°C), 7.2%–10.0% (9.9%–15.0%), and 26.6%–33.1% (36.1%–55.3%) by the early (middle) subperiod.</div><div>摘要</div><div>近年来, 随着全球变暖, 大部分地区极端气候事件的风险都有所增加. 作为中国一带一路建设核心区域的亚洲干旱区和青藏高原区域面临着严峻的极端气候风险. 本文利用NEX-GDDP-CMIP6数据预估了未来21世纪早期 (2026–2045) 和中期 (2041–2060) 不同排放情景下亚洲干旱区和青藏高原相较气候参考期 (1995–2014) 极端高温指数和极端降水指数的变化. 预估结果显示, 在不同排放情景下极端高温指数和极端降水指数都有所上升, 且在SSP5-8.5情景下增长最多, 其中NEX-GDDP-CMIP6不同模式对极端高温指数的模拟一致性高于极端降水指数. 21世纪中期相比早期极端高温指数和极端降水指数的增长更加严重.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 3","pages":"Article 100534"},"PeriodicalIF":2.3,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141398743","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":"Analyzing uncertainty and constraining projections for future vegetation in mid-to-high-latitude Asia","authors":"Jiangfeng Wei ,&nbsp;Ye Pu ,&nbsp;Xiaocong Liu ,&nbsp;Yufeng Shan ,&nbsp;Botao Zhou","doi":"10.1016/j.aosl.2024.100522","DOIUrl":"10.1016/j.aosl.2024.100522","url":null,"abstract":"<div><div>Mid-to-high-latitude Asia (MHA) is one of the regions most impacted by global warming and is highly vulnerable to the effects of climate change on its ecosystems. The future vegetation changes in this region are still uncertain, warranting a comprehensive investigation. In this study, the authors conducted a comparative analysis of leaf area index (LAI) projections by models in phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP5 and CMIP6, respectively) under high emission scenarios (RCP8.5 and SSP5–8.5, respectively). It was found that the CMIP6 models offer greater consistency with historical observations and demonstrate reduced prediction uncertainty compared to the CMIP5 models. There are strong linear relationships between the historical and future vegetation characteristics among the CMIP6 models, which enables a constrained projection of future vegetation based on historical vegetation observations. The model projections suggest a prospective overall increase in the mean, interannual variability, and seasonal amplitude of LAI in the MHA region in the future period (2061–2100) in comparison to the historical period (1985–2014). These results underscore the imperative need to enhance the understanding of ecosystem responses to climate extremes in this region.</div><div>摘要</div><div>亚洲中高纬地区是受全球变暖影响最严重的地区之一, 其生态系统高度受到气候变化的影响. 然而, 该地区未来植被变化仍不确定, 需要进行全面调查. 在这项研究中, 作者比较分析了耦合模式比较计划第五和第六阶段 (CMIP5和CMIP6) 中高排放情景 (分别为RCP8.5和SSP5–8.5) 下的叶面积指数 (LAI) 预测. 分析发现, CMIP6模式的LAI结果与历史观测数据更为一致, 并且相比CMIP5模式表现出更小的预测不确定性. CMIP6模式的历史和未来植被特征之间具有强线性关系, 这使得基于历史植被观测进行未来植被预测成为可能. 预测表明, 未来 (2061–2100年) 与历史时期 (1985–2014年) 相比, 亚洲中高纬度地区LAI的平均值, 年际变率和季节振幅将整体增加. 研究结果强调了提高对该地区生态系统应对气候极端事件的理解的重要性.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 3","pages":"Article 100522"},"PeriodicalIF":2.3,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141280053","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 maximum sea surface salinity tongue in the North Brazil continental shelf","authors":"Maria Cadima ,&nbsp;Paola Castellanos ,&nbsp;Estrella Olmedo ,&nbsp;Joaquim Dias ,&nbsp;Edmo J.D. Campos","doi":"10.1016/j.aosl.2024.100521","DOIUrl":"10.1016/j.aosl.2024.100521","url":null,"abstract":"<div><div>The variability of the sea surface salinity measurements provided by the Soil Moisture and Ocean Salinity mission reveals the presence of a local salinity maximum (a salty tongue) in the northwestern tropical Atlantic. The sea surface salinity positive anomaly starts increasing in July, reaches its maximum in January, and then disappears. The local maximum of salinity appears in the late boreal autumn/winter, when the Amazon discharge is minimal and the salty water from the South Atlantic is transported by the North Brazil Current along the shelf break across the equator. The authors validate the satellite observations in this area and assess the vertical structure of the salinity maximum by using <em>in situ</em> measurements and an <em>in situ</em>-interpolated product.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 3","pages":"Article 100521"},"PeriodicalIF":2.3,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868402","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":"Improving subseasonal forecasting of East Asian monsoon precipitation with deep learning","authors":"Jiahui Zhou ,&nbsp;Fei Liu","doi":"10.1016/j.aosl.2024.100520","DOIUrl":"10.1016/j.aosl.2024.100520","url":null,"abstract":"<div><div>Accurate subseasonal forecasting of East Asian summer monsoon (EASM) precipitation is crucial, as it directly impacts the livelihoods of billions. However, the prediction skill of state-of-the-art subseasonal-to-seasonal (S2S) models for precipitation remains limited. In this study, the authors developed a convolutional neural network (CNN) regression model to enhance the prediction skill for weekly EASM precipitation by utilizing the more reliably predicted circulation fields from dynamic models. The outcomes of the CNN model are promising, as it led to a 14 % increase in the anomaly correlation coefficient (ACC), from 0.30 to 0.35, and a 22 % reduction in the root-mean-square error (RMSE), from 3.22 to 2.52, for predicting the weekly EASM precipitation index at a leading time of one week. Among the S2S models, the improvement in prediction skill through CNN correction depends on the model's performance in accurately predicting circulation fields. The CNN correction of EASM precipitation index can only rectify the systematic errors of the model and is independent of whether the each grid point or the entire area-averaged index is corrected. Furthermore, u200 (200-hPa zonal wind) is identified as the most important variable for efficient correction.</div><div>摘要</div><div>东亚夏季风(EASM)降水的准确次季节预报至关重要, 因为它直接影响着数十亿人的生计. 然而, 最先进的次季节-季节(S2S)预测模型的预测技巧仍然有限. 本研究开发了一种卷积神经网络(CNN)回归模型, 通过利用动力预测模型预测的更可靠的环流场来提高EASM周降水的预测技巧. 经过CNN模型的订正, 在提前一周预测EASM降水指数时, 11个S2S模式的平均距平相关系数从增加了14 %, 从0.30增加到0.35; 均方根误差减少了22 %, 从3.22减少到2.52. 在这些S2S模式中, 通过CNN订正对预测技巧的提高程度取决于模式在准确预测大气环流变量方面的表现. 对EASM降水指数的CNN订正只能订正模式的系统误差, 与逐个网格订正还是整个区域平均指数订正无关, 并且在不同的提前期内CNN的订正效果基本不变. 此外, 200hPa纬向风被认为是有效订正的最重要变量.</div></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 3","pages":"Article 100520"},"PeriodicalIF":2.3,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868401","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}