设为首页
加入收藏
江淮地区夏季雨量与北半球500 hPa环流遥相关的不稳定性
INSTABILITY OF INTERANNUAL TELECONNECTIONS BETWEEN THE SUMMER RAINFALL IN JIANGHUAI REGIONS AND THE 500 hPa CIRCULATION IN NORTHERN HEMISPHERE
-
摘要: 用50年 (1951~2000年) 观测资料, 分成1951~1976年和1977~2000年两个时段, 研究了江淮地区夏季 (6~8月) 雨量与北半球500 hPa季平均环流时滞遥相关的年代际变化, 同时提出了遥相关不稳定指数, 讨论了遥相关不稳定性的空间分布和季节变化。结果表明, 这两个时段遥相关的空间分布存在显著差异, 且前一时期时滞遥相关强度明显强于后一时期, 特别是江淮地区夏季雨量与前期冬季西太平洋型 (WP) 的相关仅在1976年以前显著, 1977年以后迅速减弱消失, 而对于后一时期, 与春季欧亚遥相关型 (EU) 的相关明显加强。另外, 后一时期江淮地区夏季雨量与夏季EAP波列的相关明显强于前一时期。它反映了太平洋年代际振荡 (PDO) 对东亚季风降水和环流年际相关的影响, 这种遥相关的不稳定性与年代际和年际时间尺度振荡之间的相互作用有密切联系。Abstract: The interdecadal variations of the interannual teleconnections between the summer rainfall in the Jianghuai regions and the 500 hPa height field anomalies over the Northern Hemisphere are studied based on both sets for two periods 1957-1976 and 1977-2000. A teleconnection instabitity index is introducted, and the spatial and seasonal variations of the instability are discussed. Results show that difference of the teleconnection spatial distributions for two periods is dominant, in which the intensity of lagged teleconnection is stronger for the former period than the latter. Correlation of WP pattern in winter with summer rainfall in Jianghuai regions shows a coherent region of strong correlation before 1976 and no region with statistically significant correlation thereafter, but the correlation with EU pattern in spring was stronger for the latter period, and in the summer the correlation of EAP wave train with the rainfall is more significant for the latter than the former. It is resulted from the effects of Pacific decadal oscillation (PDO) on the interannual relationships between the East Asian monsoon rainfall and the circulation. This instability of the teleconnections is closely related to the interaction between interannual and interdecadal variations.
-
图 1 1952~2000年夏季江淮地区雨量距平变化以及主要周期和夏季北半球高度距平场的年代际变化 (a) 夏季江淮地区雨量距平变化曲线 (单位:mm), (b) 非整数功率谱分析对应统计量F值 (实线:1952~1976年期间; 虚线:1977~2000年期间, 当F=3.47时, 达0.05信度), (c)1977~2000年和1951~1976年期间夏季北半球500 hPa高度距平平均差值的空间分布
(等值线间隔是4, 单位:gpm)
图 2 1952~1976年期间江淮地区夏季雨量与前期北半球500 hPa高度场的遥相关 (a) 上年秋季, (b) 上年冬季, (c) 当年春季, (d) 同期夏季
(图中数值已乘以100, 等值线间隔是20, 虚线表示负值。当相关系数大于0.40时, 达0.05信度)
图 3 1977~2000年期间江淮地区夏季雨量与前期北半球500 hPa高度场的遥相关
(a) 上年秋季, (b) 上年冬季, (c) 当年春季, (d) 同期夏季 (说明同图 1)
图 4 1952~2000年期间500 hPa高度距平与夏季江淮下游降水距平变化曲线
((a)、(b) 中实线分别是冬季西太平洋型 (WP) 指数和春季西西伯利亚500 hPa高度距平; 虚线是夏季江淮下游降水距平)
图 5 1952~2000年期间500 hPa高度距平与夏季江淮下游降水距平之间滑动相关系数变化曲线
(a) 冬季西太平洋型 (WP) 指数; (b) 春季西西伯利亚500 hPa高度距平 (图中水平虚线表示达到0.05信度的相关系数|r0.05|=0.45))
图 6 江淮地区夏季雨量与前期北半球500 hPa高度场遥相关不稳定指数S对应的统计量|T|的空间分布
(a) 上年秋季, (b) 上年冬季, (c) 当年春季, (d) 同期夏季 (图中数值已乘以10, 等值线间隔是20(仅给出大于20的等值线) 当|T|=2.05时, 达0.05信度, 当|T|=2.77时, 达0.01信度)
表 1 夏季500 hPa高度和海温主要年际振荡周期的年代际变化
表 2 夏季江淮地区雨量与北半球500 hPa环流遥相关不稳定区域的季节变化
-
[1] Trenberth K. Recent observed interdecadal climate changes in the Northern Hemisphere. Bull Amer Meteor Soc, 1990, 71: 988-993. doi: 10.1175/1520-0477(1990)071<0988:ROICCI>2.0.CO;2 [2] Zhang Y, Wallace J M, Battisti D S. ENSO-Iike interdecadal variability: 1900-93. J Climate, 1997, 10: 1004-1020. doi: 10.1175/1520-0442(1997)010<1004:ELIV>2.0.CO;2 [3] Wu Renguang. A mid-latitude Asian circulation anomaly pattern in boreal summer and its connection with the Indian and East Asian summer monsoons. Int J Climatol, 2002, 22(15): 1879-1895. doi: 10.1002/(ISSN)1097-0088 [4] Tanaka M. Interannual and interdecadal variations of the western North Pacific monsoon and Baiu rainfall and their relationship to the ENSO cycle. J Meteor Soc Japan. 1997, 75: 1109-1123. [5] Lau K M, Weng H. Interannual, decadal-to-interdecadal and global warming signals in sea surface temperature during 1955-1997. J Climate, 1999, 12: 1257-1267. doi: 10.1175/1520-0442(1999)012<1257:IDIAGW>2.0.CO;2 [6] Hu Yongyun, Tung Ka Kit. Interannual and decadal variations of planetary wave activity, stratospheric cooling, and Northern Hemisphere annular mode. J Climate, 2002, 15(13): 1659-1673. doi: 10.1175/1520-0442(2002)015<1659:IADVOP>2.0.CO;2 [7] Allan R J, Lindesay J A, Reason C J C. Multidecadal variability in the climate system over the Indian Ocean region during the austral summer. J Climate, 1995, 8: 1853-1873. doi: 10.1175/1520-0442(1995)008<1853:MVITCS>2.0.CO;2 [8] Folland C K, Palmer T N, Parker D E. Sahel rainfall and worldwide sea temperatures 1901-85. Nature, 1986, 320: 602-607. doi: 10.1038/320602a0 [9] Kumar K, Rajagopalan K B, Cane M A. On the weakening relationship between the Indian monsoon and ENSO. Science, 1999, 284: 2156-2159. doi: 10.1126/science.284.5423.2156 [10] Janicot S, Trzaska S, Poccard I. Summer Sahel-ENSO teleconnection and decadal time scale SST variations. Climate Dyn, 2001, 18:303-320. doi: 10.1007/s003820100172 [11] Chang C P, Zhang Y, Li T. Interannual and interdecadal variations of East Asia summer monsoon and tropical Pacific SSTs. Part Ⅰ:Roles of the subtropical ridge. J Climate, 2000, 13(24): 4310-4325. doi: 10.1175/1520-0442(2000)013<4310:IAIVOT>2.0.CO;2 [12] Chang C P, Zhang Y, Li T. Interannual and interdecadal variations of East Asia summer monsoon and tropical Pacific SSTs. Part Ⅱ: Meridional structure of the monsoon. J Climate, 2000, 13(24): 4326-4340. doi: 10.1175/1520-0442(2000)013<4326:IAIVOT>2.0.CO;2 [13] 杨秋明.冬季大尺度流型与夏季中国降水量.气候与环境研究, 1998, 3(1):65-72. http://www.cnki.com.cn/Article/CJFDTOTAL-QHYH801.005.htm [14] 杨秋明.初夏亚洲季风区环流低频振荡与长江下游持续暴雨.应用气象学报, 1993, 4(3): 320-326. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=19930355&flag=1 [15] Wallace J M, Gutzler D S. Teleconnection in the geopotential height field during the Northern Hemisphere winter. Mon Wea Rev, 1981, 109: 784-812. doi: 10.1175/1520-0493(1981)109<0784:TITGHF>2.0.CO;2 [16] 黄荣辉, 孙凤英.热带西太平洋暖池的热状态及其上空的对流活动对东亚夏季气候异常的影响.大气科学, 1994, 18(2):141-151. http://www.cnki.com.cn/Article/CJFDTOTAL-DQXK199402001.htm [17] 毛江玉, 谢安, 宋森云, 等.海温及其变化对南海夏季风爆发的影响.气象学报, 2000, 58(5): 556-569. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB200005004.htm [18] Li Chongyin, Long Zhenxia, Zhang Qingyun. Strong/weak summer monsoon activity over the South China Sea and atmospheric intraseasonal oscillation. Advances in Atmospheric Sciences, 2001, 18(6):1146-1160. doi: 10.1007/s00376-001-0029-x -
下载:
计量
- 摘要浏览量: 3618
- HTML全文浏览量: 582
- PDF下载量: 1333
- 被引次数: 0
