| 关于西太平洋副热带高压的垂直环流结构和年际变动特征及其机制研究 |
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| 作者姓名： | He Jinhai Zhou Bing Wen Min Li Feng |
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| 作者单位： | He Jinhai Nanjing Institute of Meteorology. Nanjing 210044 ZhouBing LASG. In.vtitute of Atmospheric Physics，Chinese Academy of Sciences，Beijing 100029 Wen Min; and Li Feng Nanjing Institute of Meteorology. Nanjing 210044 |
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| 基金项目： | The National Natural Science Foundation of China (No.49635170)，The program of Study on Regional Climate Variation and Mechani |
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| 摘 要： | 采用１９９８年南海季风试验期间的高质量高分辨资料和ＮＣＥＰ提供的４０年再分析资料以及相关的海温和副高参数资料，研究了西太平洋副热带高压的垂直环流结构和年际变动特征及其与东亚副热带夏季风和外强迫的关系。发现在月平均图上，西太平洋副高中心（或脊线）附近看不到下沉气流，但在候平均图和日平均图上脊线附近的若干区域下沉气流明显。这表明西太平洋副高的准定常和瞬变部分的环流结构特征有显著不同。在副高北侧东亚副热带季风雨带上有暴雨发生时，其凝结海热激发的经圈环流对相应经度上的副高脊线附近的下沉气流有显著贡献。分析表明，脊线附近高（低）空的下沉气流分别来自副高北（南）侧，表明副高是中高纬和低纬度系统相互联结的纽带。相关统计指出，夏季西太平洋副高的三个参数（面积、强度和脊线纬度）与长江中下游降水存在很高的相关，降水偏多（少），副高面积偏大（小），强度偏强（弱），脊线偏南（北），这说明与降水相应的凝结潜热对副高的年际异常有重要影响。近海海温和东亚海陆热力差指数与夏季长江中下游降水和副高三参数均存在显著的相关，这表明东亚经向和纬向海陆热力差是影响副热带夏季降水和西太平洋副高年际变化的基本因子。数值试验结果指出，近海海温异常所形成的
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| 关 键 词： | 西太平洋副热带高压 经(纬)圈环流 年际变化 近海海温 |
| 收稿时间： | 17 July 2000 |
Vertical circulation structure,interannual variation features and variation mechanism of western pacific subtropical high |
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| He Jinhai,Zhou Bing,Wen Min,Li Feng.Vertical circulation structure,interannual variation features and variation mechanism of western pacific subtropical high[J].Advances in Atmospheric Sciences,2001,18(4):497-510. |
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| Authors: | He Jinhai Zhou Bing Wen Min Li Feng |
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| Affiliation: | Nanfing Institute of Meteorology. Nanjing 210044,LASG, lnstitute of Atmnospheric Physics, Chinese Academy of Sciences, Beijing 100029,Nanfing Institute of Meteorology. Nanjing 210044,Nanfing Institute of Meteorology. Nanjing 210044 |
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| Abstract: | The paper investigates the vertical circulation structure of the western Pacific subtropical high (STH) and its interannual variation features in relation to East Asian subtropical summer monsoon and external thermal forcing by using the high-resolution and good-quality observations from the 1998 South China Sea Summer Monsoon Experiment (SCSMEX), the NCEP 40-year reanalysis data and relevant SST and the STH parameters. It is found that the vertical circulation structures differ greatly in features between quasi-stationary and transient components of the western Pacific STH. When rainstorms happen in the rainkband of East Asian subtropical monsoon on the STH north side, the downdrafts are distinct around the ridge at a related meridian. The sinking at high (low) levels comes from the north (south) side of the STH,thereby revealing that the high is a tie between tropical and extratropical systems. The analyses of this paper suggest that the latent heat release associated with subtropical monsoon precipitation, the offshore SST and East Asian land-sea thermal contrast have a significant effect on the STH interannual anomaly. Our numerical experiment shows that the offshore SSTA-caused sensible heating may excite an anomalous anticyclonic circulation on the west side, which affects the intensity (area) and meridional position of the western Pacific STH. |
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| Keywords: | Western Pacific subtropical high Meridional/zonal circulation Interannual variation Offshore sea surface temperature |
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