摘要
基于诊断,本文计算了1982~2014年江南春雨的开始时间、结束时间和总降水量,分析了江南春雨的气候特征和年际变化,探讨了前冬Nino3.4区域海温异常与江南春雨的联系及可能机理。结果表明,江南春雨的起止时间和总降水量都具有显著的年际变化,前冬赤道东太平洋海温与江南春雨总量存在显著的正相关。前冬Nino3.4指数为正时,一方面通过Walker环流在赤道120°E附近区域激发出异常下沉运动以及低层异常反气旋,增强了南海地区低层西南气流以及水汽输送,另一方面与东太平洋海温变化相联系的印度洋增暖在赤道印度洋引发低层东风和孟加拉湾北部反气旋环流异常,进一步增强了江南地区的水汽输送;高层南亚地区则存在西风异常,对应江南上空辐散和抽吸作用加强,导致上升运动进一步增强,使得江南春雨总量增加;前冬Nino3.4指数为负时则次年春雨偏少;并且前冬El Ni?o事件的强度对春雨异常也有影响,前冬El Ni?o强(弱)的年份,海温异常的信号能(不能)持续到春季,江南春雨总量通常偏多(偏少)。另外,加入了前冬南极涛动指数和印度洋海盆一致模所建立的江南春雨总量的多元线性回归方程,其回归结果比基于单独的Nino3.4指数能更好地反映江南春雨的异常,可用于季节预测。
Based on analysis of observations,we defined the starting and ending time and the total rainfall of the spring persistent rainfall in Jiangnan of China(SPRJ) from 1982 to 2014,and investigated the climatic characters of the SPRJ aswell as its interannual variation.The relationship between the SST anomaly of Nino3.4 region in the preceding winter and the SPRJ and its physical mechanism were further studied.Results show that there is a significant positive correlation between the preceding winter Nino3.4 index and total SPRJ.The warm water can trigger an anomalous Walker circulation that leads to significant abnormal descending motions and corresponding low-level anticyclonic circulation near 120°E at the equator.The strengthened southwesterly winds of the anticyclone in the low level of the South China Sea facilitate more water vapor transport from the South China Sea to Jiangnan of China.On the other hand,the Indian Ocean SST anomaly associated with El Ni?o events can induce abnormal low level easterly winds in tropical Indian Ocean and anticyclone in the north of the Bay of Bengal,which also promotes the water vapor transportation.Meanwhile,the westerly anomalies in the upper troposphere above South Asia enhances divergence and pumping above Jiangnan of China,and thus are favorable for ascending motions and more SPRJ.In contrast,there is less SPRJ following a La Ni?a event.Moreover,the influence of El Ni?o on the SPRJ changes with its original intensity.With a strong El Ni?o in the preceding winter,the SSTA in the Pacific can persist to the following spring and there will be more SPRJ rainfall; with a weak El Ni?o in the preceding winter,however,the SSTA in the Pacific cannot persist to the following spring and the SPRJ total rainfall will decrease.Besides,when considering the combined effects of Nino3.4 index and Antarctic Oscillation Index and Indian Ocean Basin Mode of the preceding winter,the seasonal prediction is improved.Thus the multiple linear regression of the three predictors is useful for the prediction of the SPRJ.
引文
包澄澜.1987.中国天气学[M].北京:海洋出版社,269pp.Bao Chenglan.1987.Synoptic Meteorology in China(in Chinese)[M].Beijing:China Ocean Press,269pp.
陈丹,朱克云,布和朝鲁.2012.前期印度洋海温异常对中国春季降水的影响[J].成都信息工程学院学报,27(5):479-484.Chen Dan,Zhu Keyun,Buhe Cho-law.2012.The influence of the preceding SST of Indian Ocean on the spring precipitation in China[J].J.Chengdu Univ.Inform.Technol.(in Chinese),27(5):479-484,doi:10.3969/j.issn.1671-1742.2012.05.009.
Chen J M,Li T,Shih C F.2008.Asymmetry of the El Ni?o-spring rainfall relationship in Taiwan[J].J.Meteor.Soc.Japan Ser.II,86(2):297-312,doi:10.2151/jmsj.86.297.
陈绍东,王谦谦,钱永甫.2003.江南汛期降水基本气候特征及其与海温异常关系初探[J].热带气象学报,19(3):260-268.Chen Shaodong,Wang Qianqian,Qian Yongfu.2003.Preliminary discussions of basic climatic characteristics of precipitation during raining seasons in regions south of Changjiang River and its relationship with SSTanomalies[J].J.Trop.Meteor.(in Chinese),19(3):260-268,doi:10.3969/j.issn.1004-4965.2003.03.005.
陈艺敏,钱永甫.2005.西太平洋暖池海温对华南前汛期降水影响的数值试验[J].热带气象学报,21(1):13-23.Chen Yimin,Qian Yongfu.2005.Numerical study of influence of the SSTA in western Pacific warm pool on precipitation in the first flood period in South China[J].J.Trop.Meteor.(in Chinese),21(1):13-23,doi:10.3969/j.issn.1004-4965.2005.01.002.
程慧萍,贾晓静.2014.印度洋冬季海温异常对中国春季降水的影响[J].高原气象,33(3):733-742.Cheng Huiping,Jia Xiaojing.2014.Influence of sea surface temperature anomalies of Indian Ocean in winter on precipitation over China in spring[J].Plateau Meteor.(in Chinese),33(3):733-742,doi:10.7522/j.issn.1000-0534.2013.00024.
邓立平,王谦谦.2002.华南前汛期(4~6月)降水异常特征及其与我国近海海温的关系[J].热带气象学报,18(1):45-55.Deng Liping,Wang Qianqian.2002.On the relationship between precipitation anomalies in the first raining season(April-June)in southern China and SST over offshore waters in China[J].J.Trop.Meteor.(in Chinese),18(1):45-55,doi:10.3969/j.issn.1004-4965.2002.01.006.
Feng J,Li J P.2011.Influence of El Ni?o Modoki on spring rainfall over South China[J].J.Geophys.Res.,116(D13):D13102,doi:10.1029/2010JD015160.
高由禧,徐淑英,郭其蕴,等.1962.东亚季风的若干问题[M].北京:科学出版社,49-63.Gao Youxi,Xu Shuying,Guo Qiyun,et al.1962.Some Problems about East Asian Monsoon(in Chinese)[M].Beijing:Science Press,49-63.
胡俊.2014.青藏高原热力作用和印度洋海盆一致模对东亚夏季风年际变率的协同影响及相互作用[D].中国科学院大气物理研究所硕士学位论文.Hu Jun.2014.Coordinated impacts of the Tibetan Plateau thermal forcing and Indian Ocean Basin Mode on East Asian summer monsoon and their interactions[D].M.S.thesis(in Chinese),Institute of Atmospheric Physics,Chinese Academy of Sciences.
Kobayashi S,Ota Y,Harada Y,et al.2015.The JRA-55 reanalysis:General specifications and basic characteristics[J].J.Meteor.Soc.Japan.Ser.II,93(1):5-48,doi:10.2151/jmsj.2015-001.
李麦村,潘菊芳,田生春,等.1977.春季连续低温阴雨天气的预报方法[M].北京:科学出版社,92pp.Li Maicun,Pan Jufang,Tian Shengchun,et al.1977.The Forecast Method of Spring Persistent Low-Temperature and Rains(in Chinese)[M].Beijing:Science Press,92pp.
Liebmann B,Smith C A.1996.Description of a complete(Interpolated)outgoing longwave radiation dataset[J].Bull.Amer.Meteor.Soc.,77:1275-1277.
马慧,陈桢华,姜丽萍,等.2009.华南前汛期降水与我国近海海温的SVD分析[J].热带气象学报,25(2):241-245.Ma Hui,Chen Zhenhua,Jiang Liping,et al.2009.SVD analysis between the annually first raining period precipitation in the South of China and the SST over offshore waters in China[J].J.Trop.Meteor.(in Chinese),25(2):241-245,doi:10.3969/j.issn.1004-4965.2009.02.017.
Mao J Y,Chan J C L,Wu G X.2004.Relationship between the onset of the South China Sea summer monsoon and the structure of the Asian subtropical anticyclone[J].J.Meteor.Soc.Japan Ser.II,82(3):845-859,doi:10.2151/jmsj.2004.845.
苗秋菊,徐祥德,张胜军.2005.长江流域水汽收支与高原水汽输送分量“转换”特征[J].气象学报,63(1):93-99.Miao Qiuju,Xu Xiangde,Zhang Shengjun.2005.Whole layer water vapor budget of Yangtze River valley and moisture flux components transform in the key areas of the Plateau[J].Acta Meteor.Sinica(in Chinese),63(1):93-99,doi:10.11676/qxxb2005.010.
强学民,杨修群.2013.华南前汛期降水异常与太平洋海表温度异常的关系[J].地球物理学报,56(8):2583-2593.Qiang Xuemin,Yang Xiuqun.2013.Relationship between the first rainy season precipitation anomaly in South China and the sea surface temperature anomaly in the Pacific[J].Chinese J.Geophys.(in Chinese),56(8):2583-2593,doi:10.6038/cjg20130808.
Reynolds R W,Smith T M,Liu C Y,et al.2007.Daily high-resolutionblended analyses for sea surface temperature[J].J.Climate,20(22):5473-5496,doi:10.1175/2007JCLI1824.1.
尚可,何金海,朱志伟,等.2013.西太平洋暖池区热含量和海表温度与江南春雨的相关性对比研究[J].地理科学,33(8):986-992.Shang Ke,He Jinhai,Zhu Zhiwei,et al.2013.Comparison between correlations of heat content and sea surface temperature over western Pacific warm pool with spring persistent rains[J].Scientia Geographica Sinica(in Chinese),33(8):986-992,doi:10.13249/j.cnki.sgs.2013.08.986.
尚可,詹丰兴,何金海,等.2014.前期夏季西太平洋暖池热含量对江南春雨的影响及其可能机理[J].海洋学报,36(1):86-97.Shang Ke,Zhan Fengxing,He Jinhai,et al.2014.Impact of the preceding-summer heat content over western Pacific warm pool on spring persistent rain and its possible mechanism[J].Acta Oceanol.Sinica(in Chinese),36(1):86-97,doi:10.3969/j.issn.0253-4193.2014.01.010.
Tian S F,Yasunari T.1998.Climatological aspects and mechanism of spring persistent rains over central China[J].J.Meteor.Soc.Japan.Ser.II,76(1):57-71.
万日金,吴国雄.2006.江南春雨的气候成因机制研究[J].中国科学(D辑):地球科学,36(10):936-950.Wan Rijin,Wu Guoxiong.2007.Mechanism of the spring persistent rains over southeastern China[J].Sci.China Ser.D:Earth Sci.,50(1):130-144,doi:10.1007/s11430-007-2069-2.
万日金,吴国雄.2008.江南春雨的时空分布[J].气象学报,66(3):310-319.Wan Rijin,Wu Guoxiong.2008.Temporal and spatial distribution of the spring persistent rains over southeastern China[J].Acta Meteor.Sinica(in Chinese),66(3):310-319,doi:10.11676/qxxb2008.029.
万日金,王同美,吴国雄.2008a.江南春雨和南海副热带高压的时间演变及其与东亚夏季风环流和降水的关系[J].气象学报,66(5):800-807.Wan Rijin,Wang Tongmei,Wu Guoxiong.2008a.Temporal variations of the spring persistent rains and SCS subtropical high and their correlations to the circulation and precipitation of the East Asia summer monsoon[J].Acta Meteor.Sinica(in Chinese),66(5):800-807,doi:10.11676/qxxb2008.073.
万日金,赵兵科,侯依玲.2008b.江南春雨的年际变率及其影响因子分析[J].高原气象,27(S):118-123.Wan Rijin,Zhao Bingke,Hou Yiling.2008b.Interannual variability of spring persistent rain over southeastern China and its effect factor[J].Plateau Meteor.(in Chinese),27(S):118-123.
吴宝俊,彭治班.1996.江南岭北春季连阴雨研究进展[J].科技通报,12(2):65-70.Wu Baojun,Peng Zhiban.1996.Progress in persistent rainy processes in spring over areas between South of Changjiang River and North of five ridges[J].Sci.Tech.Bull.(in Chinese),12(2):65-70.
Xie S P,Kosaka Y,Du Y,et al.2016.Indo-western Pacific ocean capacitor and coherent climate anomalies in post-ENSO summer:A review[J].Adv.Atmos.Sci.,33(4):411-432,doi:10.1007/s00376-015-5192-6.
叶愈源.1993.1992年江南异常春雨的诊断研究[J].应用气象学报,4(S):118-122.Ye Yuyuan.1993.A diagnostic study of rainfall anomalies in March of 1992 for the southern China[J].Quart.J.Appl.Meteor.(in Chinese),4(S):118-122.
张博,钟珊珊,赵滨,等.2011.春季西太平洋海表面温度对我国江南春雨的影响[J].应用气象学报,22(1):57-65.Zhang Bo,Zhong Shanshan,Zhao Bin,et al.2011.The influence of the subtropical sea surface temperature over the western Pacific on spring persistent rains[J].J.Appl.Meteor.Sci.(in Chinese),22(1):57-65,doi:10.3969/j.issn.1001-7313.2011.01.006.
张洁,周天军,宇如聪,等.2009.中国春季典型降水异常及其相联系的大气水汽输送[J].大气科学,33(1):121-134.Zhang Jie,Zhou Tianjun,Yu Rucong,et al.2009.Atmospheric water vapor transport and corresponding typical anomalous spring rainfall patterns in China[J].Chinese Journal of Atmospheric Sciences(in Chinese),33(1):121-134,doi:10.3878/j.issn.1006-9895.2009.01.11.
郑菲,李建平.2012.前冬南半球环状模对春季华南降水的影响及其机理[J].地球物理学报,55(11):3542-3557.Zheng Fei,Li Jianping.2012.Impact of preceding boreal winter Southern Hemisphere annular mode on spring precipitation over South China and related mechanism[J].Chinese J.Geophys.(in Chinese),55(11):3542-3557,doi:10.6038/j.issn.0001-5733.2012.11.004.
周定文,范广洲,华维,等.2009.我国春季降水与青藏高原东南部冬季归一化植被指数变化的关系[J].大气科学,33(3):649-656.Zhou Dingwen,Fan Guangzhou,Hua Wei,et al.2009.Relationship between spring rainfall in China and winter normalized difference vegetation index in the southeast of Tibetan Plateau[J].Chinese J.Atmos.Sci.(in Chinese),33(3):649-656,doi:10.3878/j.issn.1006-9895.2009.03.20.