Abstract: The irrigation area of Jinghui canal is a main grain-producing area of Shaanxi province. Water resources such as precipitation and runoff are of vital importance to the agricultural production in the area. Analysing the characteristics of precipitation and runoff and identifying their influence factors are basis of managing water resource in irrigation areas. Singular spectrum analysis (SSA) method is employed to analyze the oscillation of precipitation and runoff time series in the irrigation area of Jinghui canal. Results reveal that the precipitation and runoff series in the irrigation area are closely related with monsoon in the east and sunspot activities, with cycle of 3-4 years, 9-12 years and 18-22 years. The precipitation in Jinghui canal is mainly affected by monsoon in the east, and is also influenced by large-scale cyclic factors like sunspots.

Key words: Jinghui canal irrigation area, singular spectrum analysis, precipitation, runoff, oscillation of time series