珠江三角洲海平面上升的影响范围

摘要

The scope influenced by sea level rise with a forecasted amplitude of 30cxn until 2030 in Zhujiang Delta is discussed in this paper. According to the 5cm and 25cm isolines of the increase in the highest flood-tidal level due to sea level rise, the influenced areas can be divided into three parts, with slight, relatively strong and very strong influences, respectively.rn The rise amplitude of the highest flood-tidal level affected by sea level rise at 54 hydrologic stations during different typical years in the future is calculated by a hydrology or hydraulics method.rn The influence scope varies with some conditions such as the amplitude of sea level rise, runoff, storm surge and extension of the estuary. The distribution of 5cm and 25cm isolines of rise amplitude of the highest flood-tidal level under six combinations for different typical years are derived. The result indicates that the typical year of 74 ·7 (July 22, 1974) represents a general condition of medium runoff and ordinary storm surge. By comparing an ordinary year with another five situations the difference of influence scope and influence degree can be analyzed. During the year with an ordinary flood and relatively strong storm surge the scope and degree are similar to the ordinary year. The influence is slight when the year of a small runoff and ordinary storm surge, and the situation of the typical year of 93 ·9 ( September 17, 1993 ) with extension of the estuary is also the same. When the excessively large-flood and general storm surge occured during a typical year of 94·6 (June 20, 1994) the influece scope and degree is relatively large. It is the most obvious during the typical year of 93 ·9 of a small runoff and very strong storm smge, without extension of the estuary. Therefore, the influence situation of the last can be considered as a typical condition to predicte the scope and degree and the representive values of the largest increase in the flood-tidal level of 24cm in the region with strong influences and 32crn in the region with very strong influences are recommended for the sea level rise by 30cm in the future.%研究讨论珠江三角洲2030年海平面上升30crn的影响范围。对54个站7种典型年最高洪潮水位的升幅进行了水文学或水力学计算。结果表明，按5crn和25cm升幅等值线的分布，可分出影响很小区、较大区、最大区。影响范围随多种条件而发生动态变化。影响最明显的是枯水、特大风暴潮、口门延伸的典型年，其最高洪潮水位升幅的代表值，在影响很小区、较大区、最大区分别为<5Cm、24cr、32cm。