Spatial and Temporal Variation Characteristics of Precipitation in North Canal Basin From 1960 to 2016

The temporal and spatial variation characteristics of precipitation in the basin are obtained by analyzing the precipitation data from 1960 to 2016 in the North Canal. The results show that: (1) The annual precipitation in the North Canal Basin has a weak downward trend as a whole, and there are alternating rising and falling characteristics between years. Uneven distribution during the year, precipitation is mainly concentrated in June to August, the average precipitation during this period accounted for 72% of the year; (2) The spatial distribution of precipitation in the basin is generally the most precipitation in the middle reaches, followed by the upper mountainous areas and the lower plains; In the seasons, the precipitation in the upper reaches of the summer is higher than that in the lower plains, and the opposite is true in winter. (3) The precipitation variation of the Northern Canal Basin is obvious, and the mutation point appeared in 1996 in the mid-1990s. This time node is consistent with the large regional pattern change of the Haihe River Basin; The periodic analysis shows that there are three periods of "bump-dry" change in the North Canal watershed, and the six oscillations on the 8-17a time scale are the most stable and significant, and the first main period is 13a.