利用 Scripps 海洋研究所 0—400m 上层海洋热含量资料和美国环境监测中心/国家大气研究中心(National
Centers for Environmental Prediction /National Center for Atmospheric Research, NCEP/NCAR)的再分析资料,  运用
经验正交分解(empirical orthogonal function, EOF)等统计方法,  研究在有 ENSO 影响和去除 ENSO 影响的情况下,
前期春季印度洋热含量如何影响南海夏季风爆发。结果表明,  在没有扣除 ENSO 信号的情况下,  热带印度洋热含
量 EOF 分解第一模态呈东西相反变化的空间分布。印度洋东部热含量为正(负)异常、西部为负(正)异常时,  南海
夏季风爆发较早(晚),  印度洋上层热含量主要通过影响热带印度洋上空大气的垂直运动和高低层辐散辐合,  进而
影响季风纬向环流的强弱,  来影响南海夏季风爆发的早晚。在扣除 ENSO 信号的情况下,  印度洋热含量 CEOF
(conditional EOF)第一模态的空间分布类似于 EOF 第一模态的空间分布;  第二模态表现为除小部分海区外,  热带
印度洋热含量呈一致变化的海盆模态。这两个模态对南海夏季风爆发的作用表现出不确定性。

The impact of springtime heat content in the Indian Ocean on the South China Sea (SCS) summer monsoon onset is
investigated using Empirical Orthogonal Function (EOF). The author uses 0-400 m upper-ocean heat content data from the
Scripps Institution of Oceanography and meteorological data from the National Centers for Environmental Prediction/National
Center for Atmospheric Research (NCEP/NCAR). The results show that under the influence of El Niño-Southern Oscillation
(ENSO) EOF1 of the heat content has a pattern of sea-saw variation between the eastern and western Indian Ocean. When the
heat content is positively anomalous in the eastern Indian Ocean and negatively anomalous in the western Indian Ocean, the
SCS summer monsoon has an early onset; otherwise the onset is delayed. The mechanism is that the heat content pattern in the
Indian Ocean affects the vertical movement and divergence field of upper and lower atmosphere over the tropical Indian Ocean
as well as the strength of zonal wind, leading to early or late onset of the SCS summer monsoon. The spatial pattern of condi-
tional EOF1 (CEOF1) of the heat content is similar to that of EOF1, while the spatial pattern of CEOF2 displays a uniform
pattern except for a small region. The relative importance of the two modes gives uncertainty of their influence on the SCS
summer monsoon onset.

中国极地科学战略研究基金项目(20080218)

[1] LAU K M, YANG S. Climatology and interannual variability of the Southeast Asian summer monsoon[J]. Advances in Atmospheric Sciences, 1997, 14: 141-162.
[2] 何敏, 宋文玲. 南海夏季风对中国夏季降水的影响及预测[C]//南海季风爆发和演变及其与海洋的相互作用. 北京: 气象出版社, 1999: 112-116.
[3] 陈永利, 胡敦欣. 南海夏季风爆发与西太平洋暖池区热含量及对流异常[J].海洋学报, 2003, 25(3): 20-31.
[4] HUANG R H, GU L, ZHOU L T, et al. Impact of the thermal state of the tropical western Pacific on Onset Date and process of the South China Sea summer monsoon[J]. Advances in Atmospheric Sciences, 2006, 23(6): 909-924.
[5] 赵永平, 吴爱明. 南海-热带东印度洋海温异常对南海夏季风影响的数值试验[J]. 热带气象学报, 2003, 19(1): 27-35.
[6] 梁肇宁, 温之平, 吴丽姬. 印度洋海温异常和南海夏季风建立迟早的关系Ⅰ.耦合分析[J]. 大气科学, 2006, 30(4): 619-634.
[7] 温之平, 梁肇宁, 吴丽姬. 印度洋海温异常和南海夏季风建立迟早的关系 II.机理分析[J]. 大气科学, 2006, 30(6): 1138-1146.
[8] AN SOON-IL. Conditional maximum covariance analysis and its application to the tropical Indian Ocean SST and surface wind stress anomalies[J]. J Climate, 2003, 16: 2932-2938.
[9] 吴国雄, 孟文. 赤道印度洋-太平洋地区海气系统的齿轮式耦合合ENSO事件I. 资料分析[J]. 大气科学, 1998, 22(4): 470-480.
[10] 吴国雄, 孟文.赤道印度洋-太平洋地区海气系统的齿轮式耦合和ENSO事件II. 数值模拟[J]. 大气科学, 2000, 24(1): 15-25.
[11] 戴念军, 谢安, 张勇. 南海夏季风活动的年际和年代际特征[J].气候与环境研究, 2000, 5(4): 363-374.
[12] GILL A E. Some simple solutions for heat induced tropical circulation[J]. Quart J Roy Meteo Soc, 1980, 106: 447-462.
[13] LI S, WANG B. Interdecadal change of the structure of the ENSO mode and its impact on the ENSO frequency[J]. Journal of Climate, 2000, 13: 2044-2055.
[14] 赵永平, 陈永利, 王凡, 等. 热带印度洋Dipole事件的两种模态[J]. 中国科学：D辑: 地球科学, 2008, 38(10): 1318-1328.