对近183年我国南海冬季风变率的探讨： 来自珊瑚氧同位素的证据*

以西沙群岛现代澄黄滨珊瑚的冬季氧同位素记录为代用指标，重建了1818—2000年的南海冬季风风速。重建序列显示1818—1954年冬季风速以每年0.009m·s^-1的速率下降，而1955—2000年下降速率明显增强为每年0.021m·s^-1，46年间风速下降达20%。整个183年中冬季风速变化具有两个完整的强—弱波动特征，其中1830s和1940s为过去近两个世纪当中冬季风速最强和最弱的时期。20世纪的冬季风速变化与南海海表温度和中国陆地气温极为相似，相位相反，并揭示了1940s和1980s年代两个特征暖期。通过对冬季风速异常和ENSO暖、冷事件的统计分析，发现大多数ENSO事件发生时与冬季风减弱相对应。

Variability of winter monsoon in the South China Sea during 1818-2000: Evidence from stable oxygen isotope records in coral

A modern massive Poritescoral was collected from the Xisha Islands in the northern South China Sea. Based on the relationship between stable oxygen isotopic data of coral and observed winter monsoon velocity (WMV), the calculated winter monsoon velocity (WMVc) record was obtained for years 1818-2000. Reconstructed WMVc sequence shows significant interannual and decadal variabilities for the last 183 years and presents two distinct declines at the rate of -0.009 m·s^-1·a^-1 for years 1818-1954 and -0.021 m·s^-1·a^-1 for years 1955-2000. Moreover, the WMVc decreased by about 20% during in the last 46 years of the 20th century. Two complete cycles of wind strength changes have been detected in the WMVc record over the past 183 years: the highest wind velocity occurred in the 1830s, whereas the lowest in the 1940s. During the 20th century, the variability of WMVc was very similar to the opposite changes of temperature records from the South China Sea and Chinese landmass, with two significant warm periods in the 1940s and 1980s. Statistics of WMVc anomalies against the El Nino-Southern Oscillation (ENSO) events show that most of the winter monsoon appeared to be weakened during the ENSO.