HISTORICAL EVOLUTION OF THE HIGH VELOCITY SYSTEM OF THE YELLOW RIVER ESTUARY IN THE PAST 50 YEARS

Historical observation data suggests that high velocity systems occurred outside the Yellow River estuary, and on a large time scale, these high velocity systems change with the alteration of the sea channels and the delta itself. This research aims to establish a mathematical model for the Yellow River estuary by using 3 different nautical charts.The tidal prediction software of "China Tide" is adopted to simulate the tide coming offshore. The calculation results show that: ①since 1962, there have been some high velocity systems outside the estuary, for examples the systems located at the Tianshuigou and Shenxiangou; ②in 1976, there were a number of small groups of high velocity systems along the coastline; ③sine 1996, there have been 3 high velocity systems located at the Wanwangou, Shenxiangou and the Qing 8 channel respectively; ④the change of high velocity system is closely related to the evolution of the coast, and the high velocity regions are always located at the place where protrude spits occur.