雨量变化对珊瑚岛礁淡水透镜体的影响

Influence of Rainfall on Freshwater Lens in a Coral Island

为探索雨量变化对珊瑚岛礁淡水透镜体的影响,应用质量守恒、Darcy定律和Ghy-ben-Herzberg比率,推导了珊瑚岛礁淡水透镜体的数学模型。根据西沙地区1989年—1998年10年的月均降雨量及最高、最低年降雨量,用有限差分法计算了永兴岛淡水透镜体的外型和贮水量的变化。结果表明,永兴岛淡水贮量4月最小,10月最大,相差值为4月贮水量的10.5%,而10年间降雨量最大和最小年淡水透镜体贮量与平水年相比,分别多16.8%和少7.2%,这一结果可用于制定淡水透镜体的开采战略,实现淡水资源的安全、科学、持续开发利用。

Mathematical model of freshwater lens in coral island was deduced by conservation of mass, Darcy＇ s law and the Ghyben-Herzberg approximation to explore the influence of rainfall on a freshwater lens in a coral island. Based on the average monthly rainfall, the maximum and the minimum annual rainfall from 1989 to 1998, the shape and pondage of freshwater lens of Yongxing Island were calculat- ed by a finite different method. Calculation results show that the pondage is minimum in April and maximum in October and the difference of the two months is 10.5% of that in April. During the 10 years, the pondage of the maximum and minimum rainfall year is 16.8% more and 7.2% less than the normal. The exploitation strategy of the freshwater lens is able to be constituted by means of the results so that the freshwater resource can be used safely, scientifically and sustainablely.