东亚持续强冬季风影响赤道海表温度初始异常的数值试验研究
IMPACTS OF PERSISTENTLY STRONG ASIAN WINTER MONSOON ON EQUATORIAL SEA SURFACE TEMPERATURE ANOMALY AS SIMULATED IN CLIMATE MODEL
-
摘要: 通过数值模拟和理论分析,文中指出在强东亚季风期间不仅在欧亚大陆和北印度洋出现强大的反气旋环流异常,而且通过海气相互作用在北太平洋西部和西北部形成异常气旋式流场;在其东南部产生异常反气旋式流场。在这种流场异常的驱动下赤道西太平洋西风加强,海面升高,海表温度上升,赤道中东印度洋和东太平洋东风加强,海面降低,海表温度下降。证明由于海表温度异常及海表温度变化趋势存在积分关系,因此持续的强东亚冬季风所强迫的沿赤道海表温度变化趋势的上述分布的强讯号可以在海洋中存在近一年之久,为尔后赤道太平洋ENSO事件的可能发展提供初始条件,也为跨季度气候预测提供前期讯号。Abstract: By comparing the out puts from control and sensitivity experiment of the LASG/IAP GOALS climate system model,the impacts of anom alous strong Asian winter monsoon on the initiation of the equator sea surface temperature (SST) anomaly in the Pacific Ocean are studied.It is shown that the strong Siberian cold bursts during winter notonly forms huge surface anticyclone over the Eurasian Continent,but also generates anom alous cyclone circulation over the western and northw estern Pacific and anti-cyclone circulation over the southeastern Pacific.The latter is shown to be a result of air-sea interaction over the Northern Pacific.It causes westerly wind anomaly,rise of sea level and increase of (SST) along the western equat orial Pacific and easterly wind anomaly and decrease in both sea level and SST along the equatorial eastern Indian and Pacific oceans.It is also shown that SST anomaly is the integral of SST tendency.Asstrong signals,the aforementioned SST chang es along the equator forced by strong w int er m onsoon can be retained in ocean as SST anomaly for more than half a year.This then provides initial conditions for the development of possible ENSO events along the equator,as well as precursors for inter-seasonal climate prediction.