应用综合Niño指数,分析了江淮下游里下河腹部地区1957-2006年间汛期降水与ENSO冷暖事件的关系及环流形势。结果显示:汛期降水与ENSO冷暖事件的遥相关具有较为显著的阶段性特征。El Niño、La Nina的翌年汛期降水分别以负、正距平偏多,汛期降水的正负距平转换出现在1970年代末左右。汛期降水与Niño指数具有2-7 a左右的相似周期,且二者在1980年前后出现了明显的相位转换。El Niño翌年汛期降水为正距平的环流场显示,东亚环流经向呈“+、-、+”高度距平配置,且副高范围扩大,偏西偏北,存在典型的梅雨锋面,雨带停留在江淮下游地区,利于降水形成。而La Nina翌年汛期降水为正距平的环流场表明,副高位置偏东偏北收缩,东亚经向环流呈“-、-”位势高度距平,低、中层分别为西南风、偏东南风距平,缺少梅雨锋面,汛期降水偏多的程度较小。
Niño index is applied to detect the relationships between Precipitation in Flood Season(PFS)and ENSO events in the inner Lixiahe region of the lower reaches of Jianghuai basin from 1957 to 2006.Results show that a nice teleconnection effect can be detected between PFS and Niño index,which reveals that precipitation anomalies tend to be positive(negative)in the year after the warm El Niño event(cold La Nina event),and there is a significant stage change for precipitation anomalies in the late 1970s and the early 1980. Also,wavelet period analysis for the PFS and the Niño index indicates that a similar period can be found in both PFS and the Niño index in a period of 2-7 years,and the wavelet coherence analysis shows a significant phase switch around 1980 as a result of the teleconnection of the sea surface temperature anomalies.Furthermore,the atmospheric circulation configuration for the ENSO events is described.For the El Niño warm events,its specific atmospheric circulation configuration can be concluded that the east Asia meridian circulation appears to be a"+,-,+"geopotential height anomaly,and the west Pacific subtropical high position is located closer to the west and the north,southwest winds prevail in the middle and lower troposphere,and there is an obvious plum rain frontal surface in the lower Jianghuai region which is beneficial for the staying of the plum rain belt,thus the staying of the plum rain belt might result in more precipitation.However,in contrast to atmospheric circulation configuration of the El Niño warm events,the specific atmospheric circulation configuration for the La Nina cold events may be summarized that the west Pacific subtropical high position tends to shrink back to the east and the north,the east Asia meridian circulation appears to be a"-,-"geopotential height anomaly,southwest winds prevail in the lower troposphere and southeast wind in the lower and middle troposphere respectively.Therefore,there is no obvious plum rain frontal surface under this specific atmospheric circulation configuration,hence there are less positive precipitation anomalies in the lower reaches of north Jianghuai basin.
[1] 佘敦先,夏军,张永勇,等.近50年来淮河流域极端降水的时空变化及统计特征.地理学报,2011,66(9):1200-1210.
[2] 盛绍学,石磊,刘家福,等.沿淮湖泊洼地区域暴雨洪涝风险评估.地理研究,2010,29(3):417-423.
[3] 郑伟,韩秀珍,王新,等.基于SSMI数据的淮河流域洪涝监测分析.地理研究,2012,31(1):45-52.
[4] 章国材,毕宝贵,鲍媛媛,等.2003年淮河流域强降水大尺度环流特征及成因分析.地理研究,2004,23(6):795-804.
[5] 叶正伟,许有鹏,潘光波.江淮平原水网区汛期雨量与洪涝水位关系:以江苏里下河腹部地区为例.地理研究,2011, 30(6):1137-1146.
[6] 叶正伟,许有鹏,徐金涛.江苏里下河地区洪涝灾害演变趋势与成灾机理分析.地理科学,2009,29(6):880-885.
[7] 魏凤英,张婷.淮河流域夏季降水的振荡特征及其与气候背景的联系.中国科学(D辑),2009,39(10):1360-1374.
[8] 黄大鹏,郑伟,张人禾,等.安徽淮河流域洪涝灾害防灾减灾能力评估.地理研究,2011,30(3):523-530.
[9] 胡娅敏,丁一汇.2000年以来江淮梅雨带北移的可能成因分析.气象,2009,35(12):37-43.
[10] 龚敬瑜,王谦谦.江淮梅雨期降水不同尺度异常与SSTA的关系.南京气象学院学报,2006,29(5):656-661.
[11] Gu W,Li C,Wang X et al.Linkage between Mei-yu precipitation and North Atlantic SST on the decadal timescale. Advances in Atmospheric Sciences,2009,26(1):101-108.
[12] 王钟睿,钱永甫.海温异常对江淮流域入梅的影响.应用气象学报,2005,16(2):193-205.
[13] 王钟睿,钱永甫.江淮梅雨的多尺度特征及其与厄尔尼诺和大气环流的联系.南京气象学院学报,2004,27(3): 317-325.
[14] 殷永红,倪允琪,史历.江淮流域夏季降水异常及与全球中低纬海温异常关系的诊断研究.南京大学学报(自然科 学),2001,37(3):358-368.
[15] 黄平,黄荣辉.El Niño事件对其衰减阶段夏季中国降水季节内演变的影响及其机理.大气科学学报,2010,33(5): 513-519.
[16] 陈月娟,周任君,武海峰.Niño1+2海区冷、暖水期西太平洋副高的特征及其对东亚季风的影响.大气科学,2002,26 (3):373-386.
[17] Torrence C,Compo G P.A practical guide to wavelet analysis.Bulletin of the American Meteorological Society,1998, 79:61-78.
[18] Grinsted A,Moore J C,Jevrejeva S.Application of the cross wavelet transform and wavelet coherence to geophysical time series.Nonlinear Processes in Geophysics,2004,11:561-566.
[19] Smith T M,Reynolds R W.Improved extended reconstruction of SST(1854-1997).Journal of Climate,2004,17: 2466-2477.
[20] 许武成,王文,马劲松,等.1951-2007年的ENSO事件及其特征值.自然灾害学报,2009,18(4):18-24.
[21] 赵亮,邹力,王成林,等.ENSO年东亚夏季风异常对中国江淮流域夏季降水的影响.热带气象学报,2006,22(4): 360-366.
[22] 宗海锋,陈烈庭,张庆云.ENSO与中国夏季降水年际变化关系的不稳定性特征.大气科学,2010,34(1):184-192.
[23] 孔春燕,屠其璞.全球背景下厄尔尼诺对中国东部汛期降水的影响,南京气象学院学报,2003,26(1):45-52.
[24] 姜大膀,王会军.20世纪后期东亚夏季风年代际减弱的自然属性.科学通报,2005,50(20):2256-2262.
[25] Ding Y H,Wang Z Y,Sun Y.Inter-decadal variation of the summer precipitation in East China and its association with decreasing Asian summer monsoon.Part I:Observed evidences.International Journal of Climatology,2008,28:1139- 1161.
[26] 卓东奇,郑益群,李炜,等.江淮流域夏季典型旱涝年大气中的水汽输送和收支.气象科学,2006,26(3):245-252.
[27] 竺可桢.东南季风与中国之雨量.地理学报,1934,1(1):1-27.
