CMIP3和CMIP5模式对北太平洋海平面气压变率主导模态的评估

Assessment of the Leading Modes of the North Pacific Sea Level Pressure Anomalies Based on CMIP3 and CMIP5

利用20世纪再分析资料(1871～2010年),分析了北太平洋(135°E～100°W、10°～65°N)海平面气压变率的前2个主导模态的时空特征,并结合CMIP3和CMIP5耦合模式模拟的结果,对比评估了两代CMIP耦合模式对北太平洋海平面气压变率主导模态的模拟效果。结果表明,北太平洋海表面气压异常变化的第1模态呈现阿留申低压型的变化特征,变率最大的中心位于阿留申群岛附近,而第2模态表现为北太平洋涛动型的变化,北面中心位于阿留申群岛偏北地区,南面中心位于30°N的中太平洋地区,南北呈现反相变化;CMIP3多模式集合仅能模拟出北太平洋海表面气压异常变率的第1模态,模拟不出第2模态,而CMIP5多模式集合对北太平洋海表面气压变率的前2个主导模态均能够较好地模拟出来。对北太平洋海表面气压异常变率的主导模态而言,CMIP5多模式集合无论在空间型还是强度、时间序列的模拟均优于CMIP3多模式集合的结果。

The spatial-temporal characteristics of two sea level pressure anomalies leading modes over the North Pacific Ocean （ 135°E - 100° W; 10°N -65 °N） were investigated using 20th Century reanalysis data sets for the period 1871 -2010, then the ability of models used in cou- pled model inter-comparison project 3 and 5 （CMIP3 and CMIP5, respectively） to simulate the two leading modes ]yas evaluated. The result of reanalysis data showed that the first mode represents well know Aleutian low pattern, while the second mode exhibits North Pacific Oscilla- tion pattern with positive anomalies centered in the north of the Aleutian Islands and negative anomalies in the central Pacific near 30oN. As for the result of multi-model ensemble mean, the CMIP5 multi-model ensemble mean can simulate the two leading modes independently while CMIP3 can simulate the first mode only. The multi-model ensemble mean of CMIP5 is improved not only in terms of spatial pattern and vari- ance but also in terms of time series as compared to CMIP3 models.