Atmospheric and Oceanic Science Letters最新文献

{"title":"Understanding the factors influencing cloud-core vertical accelerations during deep convection formation in the WRF model","authors":"Na Li ,&nbsp;Jin Wang ,&nbsp;Lingkun Ran ,&nbsp;Lei Yin ,&nbsp;Xiba Tang ,&nbsp;Yuchen Liu","doi":"10.1016/j.aosl.2023.100448","DOIUrl":"10.1016/j.aosl.2023.100448","url":null,"abstract":"<div><p>By introducing a linear diagnostic equation to compute perturbation pressure, the vertical momentum equation of the WRF model in the <em>η</em> coordinate is rederived, which constructs a direct relationship between vertical acceleration and physical factors we concern in the deep convection initiation (DCI) process. Important physical processes to the rapid growth of convective cloud are studied, aiming to fully understand the DCI process in the model. It is found that the DCI process is highly related to a cloud-core vertical acceleration. Due to this acceleration, the updraft is strengthened and the cloud is able to develop higher. Based on the diagnostic results of the vertical momentum equation, some different processes contributing to the high-level cloud-core accelerations in the model are found. A divergent pattern of the three-dimensional wind field is favorable for vertical acceleration. An inner physical process is that the horizontally convergent mass should be pumped up instantly by the vertical updraft to sustain a strong vertical acceleration. Second-order vertical inhomogeneity of perturbation geopotential also has an impact. Because of geopotential changes by vertical velocity (geopotential equation), this factor implies larger vertical motions will induce larger accelerations. The effects of the vertical gradient of perturbation potential temperature and moisture may be cancelled out since phase transitions can heat the convective air, but simultaneously decrease the water vapor content. Moisture makes a direct contribution to vertical acceleration, but is mostly cancelled out by the drag of cloud hydrometeors. Clearly understanding the direct impact of the basic prognostic variables on convection may help to identify the reason why DCI predictions within the model fail.</p><p>摘要</p><p>本文将扰动气压利用一个线性诊断关系代替, 重新推导了WRF模式框架地形追随坐标系下的垂直动量方程, 建立了垂直加速与对流触发 (DCI) 影响因子 (如温度, 水汽等) 的直接联系. 研究发现, DCI过程与对流核垂直加速相关, 三维副散, 扰动位势在垂直方向的二阶非均匀性, 扰动位温垂直梯度, 比湿及其垂直梯度, 水凝物拖曳, 均是能够直接影响垂直加速和对流触发的物理因子, 这些量与模式基本预报量相关, 通过解析基本预报量对对流发展的直接影响, 可能有助于理解模式对DCI过程预测失败的原因.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 3","pages":"Article 100448"},"PeriodicalIF":2.3,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283423001472/pdfft?md5=457d7c97d8e3f0c8a14d66b0dee2ce4d&pid=1-s2.0-S1674283423001472-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139019014","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":"Evaluation of CMIP6 model performance in simulating the PDO and its future change","authors":"Yuchun Du ,&nbsp;Huopo Chen","doi":"10.1016/j.aosl.2023.100449","DOIUrl":"https://doi.org/10.1016/j.aosl.2023.100449","url":null,"abstract":"<div><p>This study comprehensively assesses the model performance in simulating the variation of the Pacific Decadal Oscillation (PDO) in the winter time (November to March) during the historical period of 1870–2014 using 40 models from phase 6 of the Coupled Model Intercomparison Project (CMIP6). Its future change is also investigated under four Shared Socioeconomic Pathway scenarios on the basis of 17 CMIP6 models. Results show that CMIP6 models can reasonably reproduce the observed sea surface temperature anomaly mode associated with the PDO, with high spatial correlation coefficients of above 0.7. However, CMIP6 models generally perform poorly in simulating the variability of the PDO, with low correlation coefficients for most models, except FGOALS-g3 (0.57), GISS-E2-1-H (0.42), and NESM3 (0.37), which present a relatively greater correlation. The multi-model ensemble (MME) outperforms the individual models and can capture the dominant periodicity of the PDO (∼50 years), but it fails to capture the periodicity of ∼20 years. Additionally, the MME result underestimates the variability of the PDO. In response to future warming, the PDO is expected to transfer from a negative to positive phase around the 2050s. The 50-year periodicity of the PDO is projected to decrease compared to the historical period.</p><p>摘要</p><p>本文基于40个CMIP6模式输出结果, 系统评估了模式对历史时期太平洋年代际振荡(PDO)的模拟性能, 并利用其中17个模式的4种共享社会经济路径情景数据预估了PDO未来可能变化趋势. 结果表明, CMIP6模式能够合理再现PDO相关海表温度异常的空间模态, 但模式模拟PDO位相演变的能力普遍较弱. 多模式集合能够合理再现PDO的50年左右周期, 但无法模拟出其20年左右周期, 并且低估了PDO的变化幅度. 在未来变暖情景下, PDO可能在2050左右出现由负位相向正位相的转变, 同时其50年左右周期也将明显缩短.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"17 3","pages":"Article 100449"},"PeriodicalIF":2.3,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1674283423001484/pdfft?md5=671451919a23f995136bec47e0bb6f1d&pid=1-s2.0-S1674283423001484-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140649689","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":"Corrigendum to “A cloud optical and microphysical property product for the advanced geosynchronous radiation imager onboard China's Fengyun-4 satellites: The first version” [Atmospheric and Oceanic Science Letters 16 (2023) 100337]","authors":"Chao Liu ,&nbsp;Yuxing Song ,&nbsp;Ganning Zhou ,&nbsp;Shiwen Teng ,&nbsp;Bo Li ,&nbsp;Na Xu ,&nbsp;Feng Lu ,&nbsp;Peng Zhang","doi":"10.1016/j.aosl.2023.100421","DOIUrl":"10.1016/j.aosl.2023.100421","url":null,"abstract":"","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 3","pages":"Article 100421"},"PeriodicalIF":2.3,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135606906","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":"Corrigendum to “Effects of solar radiation modification on the ocean carbon cycle: An earth system modeling study” Atmospheric and Oceanic Science Letter 15 (2022) 100187","authors":"Xiaoyu Jin,&nbsp;Long Cao,&nbsp;Jingyu Zhang","doi":"10.1016/j.aosl.2023.100418","DOIUrl":"10.1016/j.aosl.2023.100418","url":null,"abstract":"","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"18 3","pages":"Article 100418"},"PeriodicalIF":2.3,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135433888","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":"Impact of the Atlantic multidecadal variability on East Asian summer climate in idealized simulations","authors":"Dong Si ,&nbsp;Liwei Yu","doi":"10.1016/j.aosl.2023.100399","DOIUrl":"10.1016/j.aosl.2023.100399","url":null,"abstract":"<div><p>The impact of the Atlantic multidecadal variability (AMV) on the East Asian summer climate is analyzed using a set of idealized simulations performed by CESM1. The results show that the AMV exerts a remote impact on the East Asian summer climate via two pathways: a midlatitude Rossby wave train and equatorial Kelvin waves. Specifically, the positive phase of the AMV can enhance the land–sea pressure contrast between the Asian continent and western North Pacific Ocean through the midlatitude Rossby wave train, and induce an anomalous anticyclone in the Northwest Pacific through exciting an equatorial Kelvin wave. These anomalies in atmospheric circulation in turn enhance the East Asian summer monsoon, leading to a northern-wet–southern-dry and warm summer climate in East Asia.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"16 5","pages":"Article 100399"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41724370","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":"Influence of three types of boreal summer intraseasonal oscillation on summer precipitation over the Yangtze River Valley","authors":"Xiangyang Cui ,&nbsp;Baoyan Zhu ,&nbsp;Bo Sun","doi":"10.1016/j.aosl.2023.100394","DOIUrl":"10.1016/j.aosl.2023.100394","url":null,"abstract":"<div><p>Previous studies have demonstrated that boreal summer intraseasonal oscillation (BSISO) active in the Indian Ocean can affect precipitation over the Yangtze River Valley (YRV). In this study, the impacts of three types of BSISO modes on precipitation over the YRV were investigated and found to vary significantly. First, moisture budget analysis indicated that the process responsible for the precipitation anomalies in all BSISO modes is moisture convergence, while moisture advection is insignificant. In the canonical mode, precipitation anomalies are negative (positive) at pentad −2 (−1 to 3) owing to a BSISO-related cyclone over the northwestern Pacific (anticyclone moving from the subtropical western to northwestern Pacific) accompanied by enhanced (suppressed) convection propagating northeastward. Comparatively, in the eastward expansion mode, precipitation anomalies are positive (negative) at pentad −2 to 0 (1 to 3) via a BSISO-related anticyclonic (cyclonic) circulation over the northwestern Pacific induced by the teleconnection effect of enhanced (suppressed) convection over the Indian Ocean. Different from the previous two BSISO modes, in the northward dipole mode, precipitation anomalies are negative (positive) at pentad −2 to 0 (1 to 3) owing to a BSISO-related cyclonic (anticyclonic) circulation, which moves from the South China Sea to the northwestern Pacific because of the propagation of enhanced (suppressed) convection.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"16 5","pages":"Article 100394"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41553683","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":"Contribution of the tropical sea surface temperature in the Arctic tropospheric warming during 1979–2013","authors":"Lingling Suo","doi":"10.1016/j.aosl.2023.100404","DOIUrl":"10.1016/j.aosl.2023.100404","url":null,"abstract":"<div><p>The contribution of the tropical sea surface temperature in the Arctic tropospheric warming during 1979–2013 was studied through simulations using the CAM6-Nor atmospheric general circulation model. Results showed that the tropical sea surface temperature explained about 30%–40% of the autumn warming and the January warming in the historical simulation. This implies that the tropical sea surface temperature could have been one of the main drivers of Arctic winter tropospheric warming between 1979 and 2013. The tropical sea surface temperature impacts generally came from a combination of the effects of the tropical central-eastern Pacific, the tropical Indo-western Pacific, and the tropical Atlantic, except for the January warming below 850 hPa, which was dominated by the tropical Indo-western Pacific impacts.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"16 5","pages":"Article 100404"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44173905","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":"Can a global mean sea-level rise reduce the Last Interglacial model–data mismatch in East Asia?","authors":"Zhiqi Qian ,&nbsp;Tianao Xu ,&nbsp;Zhongshi Zhang ,&nbsp;Chunju Huang","doi":"10.1016/j.aosl.2023.100406","DOIUrl":"10.1016/j.aosl.2023.100406","url":null,"abstract":"<div><p>The Last Interglacial (LIG), with its many reconstructions and simulations, provides an ideal analog for investigating the future warmer climate. However, there has been a persistent mismatch between simulated and reconstructed LIG climates in East Asia, with simulations generally indicating a colder and drier climate than reconstructions. In this study, utilizing the Norwegian Earth System Model (NorESM1-F), the authors investigated whether incorporating the global mean sea-level rise in LIG simulation experiments can reduce the model–data mismatch. The new experiments reveal a discernible, yet insufficient, warming and wetting effect in East Asia resulting from the sea-level rise. Therefore, the model–data mismatch remains unresolved. Based on these results, the authors explore alternative factors that may contribute to this mismatch, offering insights for future studies.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"16 5","pages":"Article 100406"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43312588","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":"Contribution of external forcing to summer precipitation trends over the Qinghai–Tibet Plateau and Southwest China","authors":"Yuying Xiang ,&nbsp;Tao Wang ,&nbsp;Hongna Xu ,&nbsp;Huijun Wang","doi":"10.1016/j.aosl.2023.100388","DOIUrl":"10.1016/j.aosl.2023.100388","url":null,"abstract":"<div><p>In the past 60 years, the global climate has undergone both rapid warming and a brief warming hiatus, while regional precipitation patterns in China have also experienced diverse and complex changes. Specifically, the factors behind the opposing trends in summer precipitation between two adjacent regions—Southwest China and the Qinghai–Tibet Plateau—are particularly intricate. After evaluating the historical runs from CMIP6 models, the authors assessed the contributions of various external forcing factors that simulated the summer precipitation trends observed over the Qinghai–Tibet Plateau and Southwest China from 1961 to 2014. The findings show that, compared to other forcing factors, greenhouse gases had a significant impact on the increase in summer precipitation over the Qinghai–Tibet Plateau, while aerosols played an important role in the decrease in summer precipitation in Southwest China.</p><p>摘要</p><p>在过去的60年中, 全球气候经历了快速变暖和短暂的变暖停滞, 而中国的区域降水也经历了多样而复杂的变化. 本文分析了1961年至2014年外强迫因子对青藏高原和中国西南地区夏季降水趋势的影响. 观测数据显示, 青藏高原的夏季降水呈增加趋势, 而中国西南地区的夏季降水呈减少趋势, 这两个相邻地区的夏季降水变化趋势相反. 利用CMIP6数据, 本文研究了不同外强迫因子对两个区域夏季降水趋势的影响. 结果表明, 温室气体对青藏高原夏季降水的增加具有显著影响, 而气溶胶在中国西南地区夏季降水减少中起主要作用.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"16 5","pages":"Article 100388"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49578264","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 the extratropical North Pacific on boreal summer Arctic circulation","authors":"Shengping He ,&nbsp;Tore Furevik ,&nbsp;Huijun Wang ,&nbsp;Fei Li ,&nbsp;Mingkeng Duan","doi":"10.1016/j.aosl.2023.100405","DOIUrl":"10.1016/j.aosl.2023.100405","url":null,"abstract":"<div><p>A distinct characteristic of the Arctic summer atmospheric circulation is the anomalous anticyclonic circulation centered over the Arctic Ocean associated with significant Arctic warming. Previous studies have related the underlying mechanisms to the earlier spring Eurasian snowmelt and the tropical Pacific forcing. Here, the authors show that the Arctic summer anomalous anticyclonic circulation is significantly related to the extratropical North Pacific sea surface temperature anomalies (SSTAs) in spring, indicating a teleconnection from the extratropical North Pacific to the Arctic. The SSTA pattern is characterized by warm anomalies in the midlatitudes of the extratropical North Pacific surrounded by significant cold anomalies, resembling the negative phase of the Pacific Decadal Oscillation (PDO) but without significant signals in the tropics (referred to as the negative PDO-like pattern). This negative PDO-like pattern in May can stimulate a Rossby wave propagating from the Bering Sea to the Arctic and lead to an anomalous Arctic anticyclone which can be sustained during summer. Meanwhile, the negative PDO-like pattern can persist to summer and induce an anomalous surface low pressure over the Bering Sea in summer. This anomalous surface low causes anomalous rising motions and induces upper-level divergence anomalies which further intensify the summer Arctic anticyclone. The upper-level tropospheric Arctic anticyclone can force anomalous adiabatic descent over the Arctic and sub-Arctic, leading to significant adiabatic heating in the Arctic. As a result, a significant warming emerges over the Arctic with the center located in the middle troposphere. The connection between the negative PDO-like SSTAs and the summer Arctic anticyclone has been confirmed by numerical experiments.</p></div>","PeriodicalId":47210,"journal":{"name":"Atmospheric and Oceanic Science Letters","volume":"16 5","pages":"Article 100405"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46979342","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}