摘要
使用美国夏威夷大学发展的中等复杂程度海洋模式(IOM)在给定表面强迫条件下模拟了热带大西洋上层海洋年际和年代际变率的时空结构.利用NCEP的41a(1958～1998年)逐月平均表面资料作为强迫场,积分海洋模式41a作为控制试验,并利用模式分别做动量(风应力)通量和热量通量无异常变化的平行试验,与控制试验作比较。对3组试验模拟上层海洋变率状况的比较,并按年际和年代际时间尺度分别分析,揭示表面风应力和热通量异常对海表面温度和温跃层深度变化的影响,并比较了其影响的相对重要性。结果表明模式成功地模拟出了热带大西洋上层海洋的变率。模式模拟的海表面温度年际变化主要表现为弱ENSO型,年代际变化表现为南、北大西洋变化相反的偶极子型。在年际时间尺度上,热力强迫和动力强迫对海表温度变化都有贡献,其中赤道外海表面温度异常(SSTA)变化主要由热通量异常引起,而近赤道SSTA的变化主要由动量异常强迫引起。在年代际时间尺度上,热通量强迫的作用远比动量强迫重要。模式不仅能够模拟SST在年际和年代际时间尺度上的变率,还能够模拟温跃层深度在年际和年代际时间尺度上的变率。年际和年代际时间尺度上,温跃层深度的变率主要由动量异常决定,热通量异常强迫的贡献很小。
An investigation for understanding relative contributions of the surface wind stress forcing and the heat flux forcing to the upper ocean variability in the tropical Atlantic is presented, with an intermediate ocean model (IOM) developed in Hawaii University. The model was integrated for 41 a as a control experiment with both anomalous wind stresses and anomalous heat fluxes. Two parallel sensitive experiments without forcing of either the wind stress anomalies or the surface heat flux anomalies were conducted. The relative importance of the two forcing factors in generating the upper ocean variabilities for the sea surface temperature (SST) and the thermocline depth was examined. This model successfully simulates the SST variations in the tropical Atlantic with a weak ENSO-like mode on the interannual time scale and a north-south dipole mode on the interdecadal time scale. The interannual SST variability is determined by both forcing factors. The heat flux forcing has more contribution outside the equator while the wind stress forcing has contribution mainly near the equator. The interdecadal dipole mode is largely controlled by the heat flux forcing. Variations of the thermocline depth in the Atlantic are dominated by the wind stress anomalies, and the heat flux forcing has nearly no contribution.
出处
《海洋学报》
CAS
CSCD
北大核心
2003年第3期8-19,共12页
基金
国家自然科学基金(40075017
40233028)
