A Study of the Difference of Low-frequency Oscillation Between the Typical Flood/Drought Years in Changjiang Valley

By analysis of streamline field with 30—60 day low-frequency for the anomalous flood year (1980) and drought year (1985) over Changjiang valley during the Meiyu season, it is found that there exists a distinct difference for the pattern of low-frequency streamline field and its propagation direction. The low-frequency wave is obvious and its propagation feature in the flood year is consistent with that in the normal year, but opposite in drought year.