Climate Change Research ›› 2011, Vol. 7 ›› Issue (5): 342-348.
Using a long-term observation dataset of typical debris flows in Jiangjiagou ravine in Xiaojiang River basin, northern Yunnan Province, this paper analyzes the relationship between debris flows and rainfall as well as that between ENSO and JJA (June, July, August) precipitation of Zhanyi and Huize regular meteorological stations in the vicinity of Jiangjiagou ravine. The results show that the number of the debris-flow occurrences in Jiangjiagou Ravine are positively related to the JJA rainfall, which is significantly negatively related to the January SST in Nino3 region. Moreover, the annual number of debris flows strongly depends on the date of the first occurrence in that year, while the precipitation of May and June which triggers the first occurrence is negatively related to the Nino3 SST in winter and spring. The debris flow in Jiangjiagou is sensitive to the heavy rainfall (>25 mm) that responds well to the Nino3 SST. This suggests that the Nino3 SST in winter and spring has a powerful influence on the occurrences of debris flows in the Xiaojiang River basin. It is found that the number of debris flows in Jiangjiagou Ravine is negatively correlated with January SST in the Nino3 region: it is smaller in E1 Ni?o phase years and larger in La Ni?a phase years. Because the Nino3 SST signal is at least 4 months ahead of debris flows, so it might provide an indicator for forecasting debris flows in the northern Yunnan. Particularly, it is possible to use the winter information of ENSO to predict debris flows in the subsequent summer in Xiaojiang River basin and its vicinity.
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