Based on monthly mean Simple Ocean Data Assimilation （SODA） products from 1958 to 2007, this study analyzes the seasonal and interannual variability of the North Equatorial Current （NEC） bifurcation latitude and t...Based on monthly mean Simple Ocean Data Assimilation （SODA） products from 1958 to 2007, this study analyzes the seasonal and interannual variability of the North Equatorial Current （NEC） bifurcation latitude and the Indonesian Throughflow （ITF） volume transport. Further, Empirical Mode Decomposition （EMD） method and lag-correlation analysis are employed to reveal the relationships between the NEC bifurcation location, NEC and ITF volume transport and ENSO events. The analysis results of the seasonal variability show that the annual mean location of NEC bifurcation in upper layer occurs at 14.33°N and ITF volume transport has a maximum value in summer, a minimum value in winter and an annual mean transport of 7.75×10^6 m^3/s. The interannual variability analysis indicates that the variability of NEC bifurcation location can be treated as a precursor of El Nino. The correlation coefficient between the two reaches the maximum of 0.53 with a time lag of 2 months. The ITF volume transport is positively related with E1 Nifio events with a maximum coefficient of 0.60 by 3 months. The NEC bifurcation location is positively correlated with the ITF volume transport with a correlation coefficient of 0.43.展开更多
基金The National Natural Science Foundation of China under contract No.41476025the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers under contract No.U1406404+3 种基金the National High Technology Research and Development Program(863 Program) of China under contract No.2013AA09A506the National Program on Global Change and Air-Sea Interaction under contract No.GASI-03-01-01-04the International Cooperation Program of State Oceanic Administration of China under contract No.QY0213022the "Strategic Priority Research Program" of the Chinese Academy of Sciences under contract No.XDA11010301
文摘Based on monthly mean Simple Ocean Data Assimilation （SODA） products from 1958 to 2007, this study analyzes the seasonal and interannual variability of the North Equatorial Current （NEC） bifurcation latitude and the Indonesian Throughflow （ITF） volume transport. Further, Empirical Mode Decomposition （EMD） method and lag-correlation analysis are employed to reveal the relationships between the NEC bifurcation location, NEC and ITF volume transport and ENSO events. The analysis results of the seasonal variability show that the annual mean location of NEC bifurcation in upper layer occurs at 14.33°N and ITF volume transport has a maximum value in summer, a minimum value in winter and an annual mean transport of 7.75×10^6 m^3/s. The interannual variability analysis indicates that the variability of NEC bifurcation location can be treated as a precursor of El Nino. The correlation coefficient between the two reaches the maximum of 0.53 with a time lag of 2 months. The ITF volume transport is positively related with E1 Nifio events with a maximum coefficient of 0.60 by 3 months. The NEC bifurcation location is positively correlated with the ITF volume transport with a correlation coefficient of 0.43.
文摘利用自主研发的受控脉冲穿孔等离子弧焊接系统及其控制模式,进行了等厚度板和变厚度板的受控脉冲穿孔等离子弧焊接工艺实验.本文中定义小孔的热滞后时间(t_L)为尾焰电压信号达到其峰值70%时所需时间(t_(VE0.7))与焊接电流达到峰值所需时间(t_(IP))之差,并测定了不同工艺条件下小孔的热滞后时间.实验结果表明,等厚度不锈钢板焊接实验条件下,小孔的热滞后平均时间是0.36 s;变厚度不锈钢板焊接实验条件下,随着试件厚度逐渐变薄,焊接电流峰值不断降低,但各个周期内小孔的热滞后时间的波动幅度不大,其平均值为0.22 s.
