| 摘要: |
| 太平洋内部副热带-热带经向翻转环流（subtropical-tropical cell，STC）是连接热带和副热带的海洋通道。由于以往海洋观测资料的匮乏，前人多利用海洋模式数据进行研究，且仅限于沿单一纬度上的STC的分析，较少涉及沿不同纬度的STC的季节变异规律。利用地转海洋学实时观测阵（array for real-time geostrophic oceanography，Argo）温盐数据、海洋再分析数据GODAS （global ocean data assimilation system）、SODA3.4.2（simple ocean data assimilation 3.4.2）、ORAS5（ocean reanalysis system 5）和大气再分析数据NCEP （National Centers for Environmental Prediction）等研究了沿不同纬度的STC的季节变异规律及其机制。结果显示：沿10°~2°S和2°~6°N，STC春季强，夏秋弱；沿7°~15°N，STC夏季偏强，冬季偏弱；沿15°~11°S，STC冬季偏强，夏季偏弱。STC季节变化主要由表面风场和西传Rossby波驱动，且在不同纬度，二者相对贡献存在差异：在10°S~6°N，STC的季节变化基本与风场季节变化一致，风场直接驱动是STC季节变化的主要因素；在15°~11°S以及7°~10°N，STC变化滞后风场3~4个月，在11°~15°N，STC变化滞后风场9个月，因此，西传Rossby波较局地风场对STC季节变化的贡献更大。本研究对于深入理解STC的变异规律及其对热带海洋气候变化的影响具有重要意义，多源海洋再分析数据的诊断对比分析也为大洋环流研究提供了重要参考。 |
| 关键词: STC 季节变化 经向输运 |
| DOI：10.11693/hyhz20210800186 |
| 分类号:P731 |
| 基金项目:国家自然科学基金，41976027号；中国科学院先导科技专项B子课题，XDB42010403号。 |
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| SEASONAL VARIABILITY OF SUBTROPICAL–TROPICAL MERIDIONAL OVERTURNING CIRCULATION IN THE PACIFIC |
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HAN Xue1,2,3,4, FENG Jun-Qiao1,2,4,5
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1.Key Laboratory of Ocean Circulation and Waves, Chinese Academy of Sciences, Qingdao 266071, China;2.Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;3.University of Chinese Academy of Sciences, Beijing 100049, China;4.Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China;5.Laboratory for Ocean Dynamics and Climate, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
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| Abstract: |
| The subtropical-tropical cell (STC) in the Pacific Ocean is an ocean channel connecting the tropical and subtropical oceans. Due to the lack of ocean observation data, mostly available studies use ocean model data only, which limited the analysis of STC along a single latitude, and were less involved in the seasonal variation of STC along different latitudes. Based on Argo (Array for Real-time Geostrophic Oceanography) temperature and salinity data, GODAS (Global Ocean Data Assimilation System), SODA3.4.2 (Simple Ocean Data Assimilation 3.4.2), ORAS5 (Ocean ReAnalysis System 5), and NCEP (National Centers for Environmental Prediction) reanalysis data, the seasonal variations of STC along different latitudes in the Pacific as well as its mechanism are investigated in this study. Results show that along 10°~2°S and 2°~6°N, STC is stronger in spring and weaker in summer and autumn; at 7°~15°N, STC is stronger in summer and weaker in winter; at 15°~11°S, STC is stronger in winter and weaker in summer. The seasonal variation of STC is mainly driven by surface wind field and westward Rossby wave, and their relative contributions are different at different latitudes: at 10°S~6°N, the seasonal variation of STC is basically consistent with the seasonal variation of wind field, indicating that the seasonal variation of STC is mainly attributed to the sea surface wind forcing; At 15°~11°S and 7°~10°N, the STC variation lags behind the wind field for 3~4 months, and at 11°~15°N, the STC variation lags behind the wind field for 9 months. Therefore, the westward propagating of the Rossby wave plays an important role in the seasonal variation of STC than that of the local wind field. This study offered insightful view for in-depth understanding of the variation of STC and its impact on tropical ocean climate change. The diagnosis and comparative analysis of multi-source ocean reanalysis data also provides an important reference for the study of ocean circulation. |
| Key words: subtropical-tropical cell (STC) seasonal variation meridional transport |
