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田佳, 杨双艳, 刘雅舒. 2023. 夏季青藏高原非绝热加热准双周振荡强度的年际变化及其与中国东部降水异常的联系[J]. 大气科学, 47(2): 327−342. doi: 10.3878/j.issn.1006-9895.2108.21106
引用本文: 田佳, 杨双艳, 刘雅舒. 2023. 夏季青藏高原非绝热加热准双周振荡强度的年际变化及其与中国东部降水异常的联系[J]. 大气科学, 47(2): 327−342. doi: 10.3878/j.issn.1006-9895.2108.21106
TIAN Jia, YANG Shuangyan, LIU Yashu. 2023. Interannual Variation of the Quasi-biweekly Oscillation Intensity of Diabatic Heating over the Tibetan Plateau during Boreal Summer and Its Relationship with Rainfall Anomaly over Eastern China [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 47(2): 327−342. doi: 10.3878/j.issn.1006-9895.2108.21106
Citation: TIAN Jia, YANG Shuangyan, LIU Yashu. 2023. Interannual Variation of the Quasi-biweekly Oscillation Intensity of Diabatic Heating over the Tibetan Plateau during Boreal Summer and Its Relationship with Rainfall Anomaly over Eastern China [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 47(2): 327−342. doi: 10.3878/j.issn.1006-9895.2108.21106

夏季青藏高原非绝热加热准双周振荡强度的年际变化及其与中国东部降水异常的联系

Interannual Variation of the Quasi-biweekly Oscillation Intensity of Diabatic Heating over the Tibetan Plateau during Boreal Summer and Its Relationship with Rainfall Anomaly over Eastern China

  • 摘要: 基于1979~2018年中国高分辨率格点降水资料、NCEP/NCAR和ERA-Interim再分析资料,分析了夏季青藏高原(简称高原)非绝热加热准双周振荡(Quasi-Biweekly Oscillation,QBWO)的主要模态(南部集中型)强度的年际变化与中国东部降水异常之间的联系,并从环流异常演变的角度进行解释。在高原QBWO年际强度偏强年,长江以南地区夏季降水异常与高原南部QBWO扰动呈显著正相关。在高原QBWO强度偏弱年,江淮地区和华南地区降水异常呈偶极型分布。进一步分析揭示,在高原QBWO强度偏强(弱)年,起源于西北太平洋地区的低纬度季节内信号主要表现为向西(西北)方向传播的特征,中高纬度准正压的季节内信号主要表现为向南(西南)方向传播的特征,且低纬度西(西北)传的信号与中高纬南(西南)传的信号共同作用引起中国不同的异常降水型。低纬度向西(西北)方向传播的QBWO信号传播至阿拉伯海(高原东南侧)后减弱消失,中高纬地区向南(西南)传播的信号与低纬度西(西北)传的信号汇合后继续向西(西北)方向传播,最终减弱消失。

     

    Abstract: Using China’s high-resolution grid rainfall data as well as the National Centers for Environmental Prediction/ National Center for Atmospheric Research (NCEP/NCAR) and ERA-Interim reanalysis data from 1979 to 2018, the relationship between the interannual variation of the main mode (southern concentrated pattern) of the quasi-biweekly oscillation (QBWO) of diabatic heating over the Tibetan Plateau (TP) during boreal summer and rainfall anomaly over eastern China is investigated. When the interannual intensity of QBWO over TP is strong, a significant positive correlation exists between the summer rainfall anomaly in the south of the Yangtze River and QBWO over southern TP. In the weak years, rainfall anomalies in the Jianghuai region and South China characterize a dipole pattern. Additionally, in the strong (weak) years, the low-latitude intraseasonal signal originating in the Northwest Pacific region mainly shows a westward (northwestward) propagation, and the mid-high-latitude quasi-barotropic intraseasonal signal mainly shows a southward (southwestward) propagation. The combined effect of signals from low latitudes propagating westward (northwestward) and mid-to-high latitudes propagating southward (southwestward) cause different abnormal rainfall patterns in China. The low-latitude QBWO signal propagating westward (northwestward) weakens and disappears after reaching the Arabian Sea (southeast of TP). The southward (southwestward) signal in the mid-high-latitude converges with the westward (northwestward) signal in the low-latitude, continues propagating westward, and finally weakens and disappears.

     

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