RELATIVE CONTRIBUTION OF INTRA-SEASONAL AND ABOVE SEASONAL COMPONENTS OF TROPOSPHERIC TEMPERATURE TO THE INTERDECADAL CHANGE OF THE SOUTH CHINA SEA SUMMER MONSOON ONSET
-
摘要: 南海夏季风爆发时间在1993/1994年出现显著的年代际提早, 探讨了大气要素场的不同时间尺度分量季节演变的年代际变异对南海夏季风爆发时间的年代际变异的相对影响作用。南海夏季风爆发时间的年代际提早与南海季风区对流层经向温度梯度季节性逆转的年代际提早有密切联系。南海季风区5月中对流层经向温度梯度年代际增强主要由季风区北部温度的年代际显著增暖造成。季内分量和季节以上分量对1993年之前南海季风区经向温度梯度逆转及加强时间偏晚的作用同等重要。经向温度梯度距平的季节以上分量主要源于季风区北部温度相应分量的贡献, 而季节内分量则主要由南部相应分量影响所致, 并由25~90 d分量所主导。季节以上分量对1994年之后南海季风区经向温度梯度逆转及加强时间偏早的贡献要大于季节内分量的贡献。经向温度梯度距平的季节以上分量和季内分量对总距平的正贡献都主要来自于季风区北部温度相应分量。两种季内低频分量对温度梯度季内分量的贡献率相当, 10~25 d分量主要由南海北部温度相应分量所主导, 25~90 d分量对总距平的正贡献也源自北部分量。准双周振荡分量对各年代南海夏季风爆发具有明显的触发作用。
-
关键词:
- 南海夏季风 /
- 爆发 /
- 年代际变异 /
- 季节内变化与季节以上变化
Abstract: The South China Sea summer monsoon (SCSSM) onset experiences evidently an interdecadal change around mid-1990 s. This study examines the relative contribution of different time-scale components of tropospheric temperature to the interdecadal change of the SCSSM onset. The interdecadal advanced onset of SCSSM is closely linked to the interdecadal advance of the seasonal reversion of temperature meridional gradient (TMG) over the SCSSM region. The interdecadal enhancement of the TMG over the SCSSM region in mid-May is mainly contributed by the evident interdecadal warming of tropospheric temperature over the northern part of the SCSSM region. Both intraseasonal and above seasonal components exert evident influence on the late seasonal reversion of TMG in the period prior to 1993. The TMG above seasonal component is mainly controlled by the corresponding counterpart of tropospheric temperature over the northern part of the SCSSM region, while the TMG intraseasonal component dominant on 25-90-day is contributed by the corresponding counterpart of tropospheric temperature over the southern part of the SCSSM region. The above seasonal component devotes a greater contribution than the intraseasonal component to the interdecadal advance of the seasonal reversion of temperature meridional gradient (TMG) over the SCSSM region in the period post 1994, and both intraseasonal and above seasonal TMG components are controlled by the counterparts over the northern part of the SCSSM region. Furthermore, the 10-25-day and 25-90-day components make an equal contribution to the intraseasonal time-scale component of TMG, and two intraseasonal components are mainly controlled by the counterparts over the northern part of the SCSSM region. The quasi-biweekly component exerts evidently a triggering effect on the SCSSM onset for each period. -
图 3 南海北部N(109.5~120.0 °E,16.5~21.0 °N)和南海南部S(109.5~120 °E,1.5 °S~3 °N)上空850~200 hPa平均的经向温度梯度(a,TN—TS)及北部温度TN(b),南部温度TS(c)的季节演变
红色、蓝色和黑色分别表示1979-1993年、1994-2010年和1979-2010年时段的平均,阴影范围表示各曲线0.5倍标准差。单位:℃。南海南部和北部区域如图 1d的矩形框所示。
图 9 同图 8,但黑色、蓝色和红色分别表示10~90 d、25~90 d和10~25 d的距平分量(单位:℃)
5月17—21日平均(1979—1993年)
表 1 南海北部N(109.5~120.0 °E,16.5~21.0 °N)和南部S(109.5~120.0 °E,1.5 °S~3.0 °N)上空850~200 hPa平均的温度TN,TS及其经向梯度TN—TS的各分量距平值(单位:℃)及贡献率
时间变量 5月17—21日平均(1979—1993年) 5月12—16日平均(1994—2010年) TN-TS TN -TS TN-TS TN -TS 总距平 -0.178(100%) -0.097(54.5%) -0.081(45.5%) 0.128(100%) 0.183(143%) -0.055(-43%) >90 d -0.094(52.8%) -0.076(80.9%) -0.018(19.1%) 0.088(68.8%) 0.081(92%) 0.007(8%) 10~90 d -0.083(46.6%) -0.023(27.7%) -0.060(72.3%) 0.052(40.6%) 0.116(223%) -0.064(-123%) 25~90 d -0.119(66.9%) -0.072(60.5%) -0.047(39.5%) 0.024(18.8%) 0.085(354%) -0.062(-254%) 10~25 d 0.036(-20.2%) 0.049(136.1%) -0.013(-36.1%) 0.028(21.9%) 0.031(110.7%) -0.002(-10.7%) 注:(1)TN-TS列中括号的百分数表示该分量距平值对占总距平的百分率;(2)TN、TS列的百分数表示该分量值占同时段同类分量的TN-TS值的百分率。 -
[1] 林爱兰, 李春晖, 郑彬, 等.南海夏季风爆发与华南前汛期锋面降水气候平均的联系[J].中山大学学报(自然科学版), 2010, 49(4): 134-143 [2] TAO S Y, CHEN L X. A review of recent research on the East Asian summer monsoon in China[M]. Chang C P, Krishnamuti T N, eds. Monsoon Meteorology. Oxford: Oxford University Press, 1987: 60-92 [3] 邵勰, 黄平, 黄荣辉.南海夏季风爆发的研究进展[J].地球科学进展, 2014, 29(10): 1 126-1 137 [4] 陈隆勋, 李薇, 赵平, 等.东亚夏季风爆发过程[J].气候环境研究, 2000, 3(4): 345-355 [5] 李崇银, 张利平.南海夏季风活动及其影响[J].大气科学, 1999, 23(2): 257-266 [6] 丁一汇, 马鹤年.东亚季风的研究现状[M].何金海, 编.亚洲季风研究的新进展.北京: 气象出版社, 1996: 1-14. [7] 李崇银.大气季节内振荡研究的新进展[J].自然科学进展, 2004, 14(7): 734-741 [8] WU R G, WANG B. Multi-stage onset of the summer monsoon over the western North Pacific[J]. Climate Dyn, 2001, 17(4): 277-289 [9] 简茂球, 罗会邦. 1998年青藏高原东部及其邻近地区大气热源与南海夏季风建立的关系[J].高原气象, 2001, 20(4):381-387 [10] 林爱兰, 谷德军, 李春晖, 等.南海夏季风爆发与华南前汛期锋面降水异常变化的联系[J].中山大学学报(自然科学版), 2010, 49(5):127-133. [11] KAJIKAWA Y, WANG B. Interdecadal change of the South China Sea summer monsoon onset[J]. J Climate, 2012, 25(9): 3 207-3 218. [12] YUAN F, CHEN W. Roles of the tropical convective activities over different regions in the earlier onset of the South China Sea summer monsoon after 1993[J]. Theoretical and Applied Climatology, 2013, 113(1/2): 175-185. [13] SIMMONS A J, UPPALA S M, DEE D P, et al. ERA-Interim: New ECMWF reanalysis products from 1989 onwards[J]. ECMWF Newsletter, 2007, 110: 25-35. [14] DEE D P, UPPALA S M, SIMMONS A J, et al. The ERA-Interim reanalysis: Configuration and performance of the data assimilation system[J]. Quart J Roy Meteor Soc, 2011, 137(656): 553-597. [15] LIEBMANN B, SMITH C A. Description of a Complete (Interpolated) Outgoing Longwave Radiation Dataset[J]. Bull Ame Meteor Soc, 1996, 77(6): 1 275-1 277. [16] 林爱兰, 谷德军, 李春晖, 等.赤道MJO活动对南海夏季风爆发的影响[J].地球物理学报, 2016, 59(1): 28-44 [17] LIU B, ZHU C. A possible precursor of the South China Sea summer monsoon onset: Effect of the South Asian High[J]. Geophys Res Lett, 2016, 43 (20): 11 072-11 079 [18] FUKUTOMI Y, YASUNARI T. 10-25-day intraseasonal variations of convection and circulation over East Asia and western North Pacific during early summer[J]. J Meteor Soc Japen, 1999, 77(3): 753-769. [19] KAJIKAWA Y, YASUNARI T. Interannual variability of the 10-25- and 30-60-day variation over the South China Sea during boreal summer[J]. Geophys Res Lett, 2005, 32, L04710, doi: 10.1029/2004GL021836. [20] ZHOU W, CHAN J C L. Intraseasonal oscillations and the South China Sea summer monsoon onset[J]. Int J Climatol, 2005, 25(12):1 585-1 609. [21] TONG H W, CHAN J C L, ZHOU W. The role of MJO and mid-latitude fronts in the South China Sea summer monsoon onset[J]. Climate Dyn, 2009, 33(6): 827-841. [22] WU R. Subseasonal variability during the South China Sea summer monsoon onset[J]. Climate Dyn, 2010, 34(5): 629-642. [23] 李春晖, 何超, 郑彬, 等.夏季(5—10月)南海准双周和20—60天振荡的年代际变化特征[J].热带气象学报, 2016, 32(5): 577-587.