长江口水文要素时空分布特征

Spatial and temporal distribution characteristics of hydrological elements in the Yangtze River Estuary

搜集实测资料分析2016—2019年大通站流量、北槽中站流速等长江口水文要素变化特征。结果表明:1)近4年,大通站径流年总量与往年平均值接近,年内最大月均流量出现在7—8月,最小值出现在10月—次年2月。2)北槽高、低潮位和潮差月平均值年内呈单峰型分布,峰值出现在8—10月;3个不同位置测站变化趋势基本一致,南槽东月平均潮位最高且潮差最大。3)北槽落急流速月平均值大于涨急且在6—8月达到峰值,涨急流速在6—8月达到低谷;落潮月平均流速大于涨潮,涨潮月平均流速在7月份达到最小;落潮历时月平均值大于涨潮且在6—8月达到峰值。4)北槽中站水温年内变化规律明显,8月月平均气温可达29.96℃,2月月平均气温为7.51℃。5)南槽东、牛皮礁、长江口月平均有效波高及周期整体变化规律基本一致;从年内分布来看有效波高变化较大、波周期变化较小;长江口站有效波高及波周期高于其他两站,南槽东站与牛皮礁站有效波高及波周期差异较小;3站总波能南槽东站最小、长江口站最大。

We Collected measured data and analyzed the variation characteristics of the hydrological elements in the Yangtze River Estuary, such as the discharge of Datong station and the velocity of the North Passage middle station from 2016 to 2019.The results show that: 1)The annual total runoff volume of Datong Station in recent four years is close to the average of previous years. The maximum monthly average flow occurs from July to August, and the minimum occurs from October to February. 2)The monthly averages of high and low tide, tidal level and tidal range in the North Passage middle station have a single-peak distribution during the year, and the peak occurs from August to October. The changing trends of the 3 different stations are basically the same. The monthly average tide level in the east of the South Passage station is the highest and the tidal range is the largest. 3)The monthly mean value of the ebb current is larger than that of the flood current in the North Passage middle station and reaches the peak from June to August. The flood current reaches the trough from June to August. The monthly average velocity of ebb tide is larger than that of flood tide. The average monthly velocity of flood tide reaches its minimum in July. The monthly average duration of low tide is larger than high tide and reaches the peak form June to August. 4)The water temperature in the North Passage middle station has an obvious change during the year. The monthly average temperature in August can reach 29. 96 ℃, and the monthly average temperature in February is 7. 51 ℃.5) The monthly average effective wave height and period of the east of the South Passage station, Niupijiao and Yangtze River Estuary are basically the same. From the perspective of annual distribution, the effective wave height changes greatly and the wave period changes little. The effective wave height and wave period of the Yangtze River Estuary station are higher than those of the other two stations. The difference between the significant wave height and wave period of the east of the South Passage station and Niupijiao is small. The total wave energy of the three stations is the smallest at the east of the South Passage station and the largest at the Yangtze River Estuary.