Indian Ocean Warm Pool Variability And Its Impact On The Asian Climate

In this paper, based on the analysis of SODA (the Simple Ocean Data Assimilation) data, NCEP/NCAR(National Centers for Environmental Prediction/National Center for Atmospheric Research)data, XBT (Expendable Bathythermograph) data, COADS (Comprehensive Ocean Atmosphere Data Sets) data and the monthly mean rainfall data at 160 observational stations in China, it is studied that the seasonal, interannual and decadal variabilities of the Indian Ocean warm pool (IOWP), the Western Pacific warm pool (WPWP) and the Indian Ocean-Western Pacific warm pool (IO-WPWP). The influence of the Indian Ocean warm pool on the spring precipitation in China and the Asian monsoon are investigated.The results show that there is obvious one-peak structure seasonal variability of the Indian Ocean-Western Pacific warm pool which is different from the two-peak structure seasonal variability of the Western Pacific warm pool. Based on the wavelet analysis and power spectrum analysis, the variability of the Indian Ocean-Western Pacific warm pool and the Western Pacific warm pool show a 3-6 years oscillation. While, there is a quasi-biennial oscillation in the Indian Ocean warm pool, which may imply the effect of monsoon. It is found that there is close relationship of the interannual variability between the Indian Ocean-Western Pacific warm pool and that of the Nin ~o3 index. The correlation coefficient between the Indian Ocean warm pool and the Nin ~o3 index reaches the maximum by the former lag about half a year. A sudden shift of the three indices of the three warm pools occurs in the middle or later of 1970s, representing an obvious decadal variability,especially in the Indian Ocean warm pool.The relationship between the variability of the India Ocean Warm Pool and the spring precipitation in China is also studied in this paper. The results show that there is a strong partial correlation between the Indian Ocean warm pool variability and the spring precipitation in China. The area indices of the Indian Ocean warm pool are negatively correlated with the spring precipitation in southwestern China, while they are positively correlated with the spring precipitation in the rest of China, especially in the northeast.For this partial correlation between the Indian Ocean warm pool variability and the spring precipitation in China, it is found that the correlative relationship is mainly connected with the variations of the moisture transport by the warm air flow, which is under the influence of the Indian Ocean warm pool variability, into the inland of China in spring. Two causative factors may influence this transport. The first is the variation of the moisture transport carried by the warm air flow from the Arabian Sea influenced by the Indian Ocean warm pool variability. The second is the position and...