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Meridional Variation of South Asian High and Its Relationship with the Summer Precipitation over China
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摘要: 该文定义了一个能较好反映南亚高压南北偏移的指数，并发现该指数与我国夏季降水，尤其是华北和长江流域的降水，无论在年际变化上还是长期趋势上都具有十分显著的相关关系。南亚高压位置偏北时，在我国东部至日本上空存在一个显著的异常反气旋，其中心自上而下向南倾斜，在高层给华北地区带来辐散，在低层使得气流在长江流域辐散，在华北地区辐合，造成华北地区降水偏多，长江流域降水偏少。同时，南亚高压偏北对应着高层西风急流以及中层西太平洋副热带高压偏北，使得我国整个雨带偏北。此外，通过与海温的相关分析发现，南亚高压的长期偏南趋势可能受到印度洋增暖的直接影响。南北偏移指数可作为预测我国夏季区域降水的重要指标，在气候预测业务中有一定的应用价值。Abstract: South Asian High (SAH) is the most intense and stable upper level anticyclone in boreal summer. As a member of the East Asian Summer Monsoon system, SAH plays an important role in the regional climate anomaly over China.The meridional variation of SAH is analyzed by using the monthly mean data derived from the European Center for Medium-Range Weather Forecasts (ECMWF) 40-year reanalysis (ERA-40) from 1958 to 2002. An index of SAH (SAHI) is defined to measure its meridional variation in summer and to analyze its relationship with the summer precipitation over China. The results show a significant correlation between the meridional position of SAH and the summer rainfall over China for both the interannual timescale variability and the long-term linear tendency. The correlation coefficients between SAHI and the summer rainfall in North China and in the Yangtze River Valleys are 0.577 and-0.604, respectively, both of which exceeds 0.01 level. When SAH locates further northward (southward), North China and South China are wetter (drier) than normal, while the Yangtze River Valleys is drier (wetter) than normal. And the southward linear trend of SAH corresponds with the decreasing trend of rainfall in North China and the increasing trend of rainfall in the Yangtze River Valleys.Linear regression analysis of the circulation reveals that when SAH locates further northward, an anomalous anticyclone controls eastern China with its center tilted southward from 200 hPa to 850 hPa. In the upper atmosphere, the anomalous anticyclone forms a divergence zone over North China. In the lower atmosphere, it results in flows diverging over the Yangtze River valley, and converging over North China. Besides, the northward movement of SAH would cause the upper-level westerly jet and the Western Pacific Subtropical High move northward, with the rainbelt locating in North China.The meridional anomalous variation of SAH is closely related to the sea surface temperature anomalies (SSTA) of the Tropical Indian Ocean (TIO), the Central and Eastern Equatorial Pacific, and the northern Pacific. And the TIO SSTA might modulate its meridional position directly. Positive TIO SSTA might lead to a southward expansion of SAH.Due to strong correlation with the summer rainfall over China and being modulated by the TIO SSTA, the meridional variation of SAHI could be considered as an important indicator used to predict the regional climate anomaly.
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图 1 南亚高压南北偏移指数的定义
(a)1958—2002年夏季平均200 hPa位势高度场 (单位：gpm)，(b) 南亚高压南北偏移指数标准化序列，(c) 南亚高压南北偏移高指数年 (实线) 和低指数年 (虚线)200 hPa位势高度场合成 (单位：gpm)
Fig. 1 Definition of the South Asian High Index (SAHI)
(a) climatology of summer geopotential height (unit: gpm) at 200 hPa from 1958 to 2002, (b) standardized time series of SAHI, (c) composites of geopotential height (unit: gpm) at 200 hPa in case of high SAHI (solid line) and low SAHI (dashed line)
图 2 南亚高压南北偏移与我国夏季降水的关系
(a) 南北指数回归的我国夏季降水异常分布 (回归系数大小由色阶表示；相关系数达到0.05显著性水平的区域用粗线标出)，(b) 华北地区降水标准化序列 (及趋势) 与南北偏移指数序列的对比，(c) 长江流域降水标准化序列 (及趋势) 与南北偏移指数序列的对比
Fig. 2 Relationship between SAHI and precipitation over China
(a) pattern of regression of anomalous precipitation over China against SAHI (correlations exceeding 0.05 level are highlighted by thick lines), (b) standardized time series of precipitation (with the linear tendency) in North China compard with SAHI series, (c) standardized time series of precipitation (with the linear tendency) in Yangtze River Valleys compared with SAHI series
图 3 南亚高压南北偏移指数回归的环流场 (矢量) 以及高度场 (等值线，单位：gpm) 异常(阴影区表示纬向风或经向风异常达到0.05显著性水平)
(a)200 hPa，(b)500 hPa，(c)850 hPa (仅环流场异常)
Fig. 3 Patterns of regression of anomalous horizontal wind (vector) and geopotential height (contour, unit: gpm) against SAHI at 200 hPa (a), 500 hPa (b) and 850 hPa (anomalous horizontal wind only)(c)(significant values of anomalous horizontal wind exceeding 0.05 level are shaded)
图 4 南亚高压南北偏移与海温异常的关系
(a)1958—2002年夏季海温异常线性变化趋势，(b) 南亚高压南北偏移指数回归的海温异常异常场 (相关系数达到0.05显著性水平的区域用粗线标出)
Fig. 4 Relationship between SAHI and SSTA
(a) linear tendency of SSTA, (b) pattern of regression of SSTA against SAHI (correlations exceeding 0.05 level are highlighted by thick lines)
图 5 标准化印度洋海温异常与南亚高压南北偏移指数的时间序列
Fig. 5 Standardized time series of Indian Ocean SSTA and SAHI with their linear tendency
表 1 南亚高压各项指数与我国各区域夏季降水的相关关系
Table 1 Correlations of SAHI to precipitation in North China and the Yangtze River Valleys
指数 华北地区 长江流域 南北偏移指数 0.577** -0.604** 面积指数 0.061 0.382** 中心强度I1 0.291 0.170 强度I2 0.175 0.323* 强度I3 0.349* 0.169 注：*表示相关系数达到0.05显著性水平，**表示相关系数达到0.01显
著性水平。另外，南北偏移指数外其余4项指数的定义[21]：① 面积指
数：区域内位势高度大于或等于12500 gpm总格点数；② 中心强度I1：
高压中心位势高度值；③ 强度I2：区域内位势高度大于12500 gpm时所
有格点上的位势高度值与12500 gpm之差的总和；④ 强度I3：I2与面积
指数之比。
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[1] Mason R B, Anderson C E. The development and decay of the 100mb summertime anticyclone over Southern Asia. Mon Wea Rev, 1963, 91: 3-12. doi: 10.1175/1520-0493(1963)091<0003:TDADOT>2.3.CO;2 [2] 陶诗言, 朱福康.夏季亚洲南部100毫巴流型的变化及其与西太平洋副热带高压进退的关系.气象学报, 1964, 34(4): 385-396. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB196404000.htm [3] 陈隆勋, 朱乾根, 罗会邦.东亚季风.北京:科学出版社, 1991. [4] 李崇银, 李琳, 谭言科.南亚高压在平流层的特征及ENSO影响的进一步研究.热带气象学报, 2011, 27(3): 289-298. http://www.cnki.com.cn/Article/CJFDTOTAL-RDQX201103001.htm [5] Krishnamurti T N, Bhalme H. Oscillations of a monsoon system. Part Ⅰ: Observational aspects. J Atmos Sci, 1976, 33: 1937-1954. doi: 10.1175/1520-0469(1976)033<1937:OOAMSP>2.0.CO;2 [6] 朱福康, 陆龙骅, 陈咸吉, 等.南亚高压.北京:科学出版社, 1980. [7] 罗四维, 钱正安, 王谦谦.夏季100毫巴青藏高压与我国东部旱涝关系的天气气候研究.高原气象, 1982, 1(2): 1-10. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX198202000.htm [8] Zhang Q, Wu G X, Qian Y F. The bimodality of the 100 hPa South Asia High and its relationship to the climate anomaly over East Asia in summer. J Meteorol Soc Jpn, 2002, 80: 733-744. doi: 10.2151/jmsj.80.733 [9] 钱永甫, 张琼, 张学洪.南亚高压与我国盛夏气候异常.南京大学学报:自然科学版, 2002, 38(3): 295-307. http://www.cnki.com.cn/Article/CJFDTOTAL-NJDZ200203004.htm [10] 陈桂英, 廖荃荪. 100 hPa南亚高压位置特征与我国盛夏降水.高原气象, 1990, 9(4): 432-438. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX199004011.htm [11] 张琼, 吴国雄.长江流域大范围旱涝与南亚高压的关系.气象学报, 2001, 59(5): 569-577. doi: 10.11676/qxxb2001.061 [12] 黄樱, 钱永甫.南亚高压与华北夏季降水的关系.高原气象, 2003, 22(6): 74-79. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200306011.htm [13] 黄燕燕, 钱永甫.长江流域、华北降水特征与南亚高压的关系分析.高原气象, 2004, 23(1): 70-76. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200401010.htm [14] 梁必琪.天气学教程.北京:气象出版社, 1995: 251-257. [15] He J, Wen M, Wang L, et al. Characteristics of the onset of the Asian Summer Monsoon and the importance of Asian-Australian "land bridge". Adv Atmos Sci, 2006, 23: 951-963. doi: 10.1007/s00376-006-0951-z [16] 何金海, 徐海明, 钟珊珊, 等.青藏高原大气热源特征及其影响和可能机制.北京:气象出版社, 2011. [17] 孙淑清, 高守亭.现代天气学概论.北京:科学出版社, 2005. [18] 尤卫红, 段长春, 赵宁坤, 等.夏季南亚高压年际变化的特征时间尺度及其时空演变.高原气象, 2006, 25(4): 601-608. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200604005.htm [19] Uppala S M, KÅllberg P W, Simmons A J, et al. The ERA-40 re-analysis. Quart J Roy Meteor Soc, 2005, 131: 2961-3012. doi: 10.1256/qj.04.176 [20] Rayner N, Brohan P, Parker D, et al. Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century: The HadSST2 dataset. J Climate, 2006, 19: 446-469. doi: 10.1175/JCLI3637.1 [21] 张琼, 钱永甫, 张学洪.南亚高压的年际和年代际变化.大气科学, 2000, 24(1): 67-78. http://www.cnki.com.cn/Article/CJFDTOTAL-DQXK200001006.htm [22] Yang J L, Liu Q Y, Xie S P, et al. Impact of the Indian Ocean SST basin mode on the Asian summer monsoon. Geophys Res Lett, 2007, 34: doi: 10.1029/2006GL028571. [23] Zhou T J, Yu R C, Zhang J, et al. Why the Western Pacific Subtropical High has extended westward since the late 1970s. J Climate, 2009, 22: 2199-2215. doi: 10.1175/2008JCLI2527.1 [24] 刘伯奇, 何金海, 王黎娟. 4～5月南亚高压在中南半岛上空建立过程特征及其可能机制.大气科学, 2009, 33(6): 1319-1332. http://www.cnki.com.cn/Article/CJFDTOTAL-NJQX201201001.htm [25] 钟水新, 王东海, 张人禾, 等.基于CloudSat资料的冷涡对流云带垂直结构特征.应用气象学报, 2011, 22(3): 257-264. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20110301&flag=1 [26] 徐祥德, 陈联寿.青藏高原大气科学试验研究进展.应用气象学报, 2006, 17(6): 756-772. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=200606124&flag=1 [27] 廖荣伟, 赵平.季风湿润区冬季水汽收支年际及年代际变化特征.应用气象学报, 2011, 22(6): 641-653. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20110601&flag=1 [28] 陈隆勋, 张博, 张瑛.东亚季风研究的进展.应用气象学报, 2006, 17(6): 711-724. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=200606120&flag=1 [29] Li S L, Lu J, Huang G, et al. Tropical Indian Ocean Basin warming and East Asian Summer Monsoon: A multiple AGCM study. J Climate, 2008, 21: 6080-6088. doi: 10.1175/2008JCLI2433.1 [30] 杨建玲, 刘秦玉.热带印度洋SST海盆模态的"充电/放电"作用——对夏季南亚高压的影响.海洋学报, 2008, 30(2): 12-19. http://www.cnki.com.cn/Article/CJFDTOTAL-SEAC200802002.htm [31] Zhang R H. Relations of water vapor transport from Indian monsoon with that over East Asia and the summer rainfall in China. Adv Atmos Sci, 2001, 18: 1005-1017. http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQJZ200105029.htm [32] Huang G, Qu X, Hu K M. The impact of the Tropical Indian Ocean on South Asian High in boreal summer. Adv Atmos Sci, 2011, 28: 421-432. doi: 10.1007/s00376-010-9224-y [33] 谭言科, 张人禾, 何金海, 等.热带印度洋海温的年际变化与ENSO.气象学报, 2004, 62(6): 831-840. http://cdmd.cnki.com.cn/Article/CDMD-10423-1015712722.htm [34] Lau N C, Nath M J. The role of the "atmospheric bridge" in linking tropical pacific ENSO events to extratropical SST anomalies. J Climate, 1996, 9: 2036-2057. doi: 10.1175/1520-0442(1996)009<2036:TROTBI>2.0.CO;2 -
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