Hydrology of Small Oceanic Islands — Influence of Atmospheric Pressure on the Water Table
Hydrology of Small Oceanic Islands — Influence of Atmospheric Pressure on the Water Table
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小海洋岛屿的水文——大气压对地下水位的影响
DOI：
10.1111/j.1745-6584.1978.tb03256.x
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发表时间：
1978
期刊：
影响因子：
2.6
通讯作者：
H. Vacher
中科院分区：
文献类型：
--
作者：
H. Vacher
一系列海平面波动会影响一个渗透性小洋岛的地下水位。频谱的高频端是天文潮汐的半日和日分量。影响海平面高度的还有大气压力以及海洋柱的温度和盐度（因此密度）。
大气压力的变化会导致海平面变化高达约 30 厘米，海洋学家称之为“倒转气压计效应”。结果，压力变化就像潮汐一样，产生穿过地下水位迁移的波浪。由此产生的与压力相关的地下水位波动幅度在内陆减小。但由于压力波动周期较长，其内陆衰减远小于水力类似潮汐。事实上，以百慕大为例，与压力相关的地下水位波动完全主导了反映海拔每日变化的地下水位统计数据。
因为压力下降和地下水位相应上升伴随着风暴锋的通过，这也带来了降雨，所以降雨和地下水位上升之间通常存在一种巧合且非常误导性的相关性。在岛屿和沿海地区，如果要根据地下水位数据正确评估补给量，就必须考虑非潮汐海平面变化及其对地下水位的影响。
There is a spectrum of sea-level fluctuations that affect the water table of a small, permeable oceanic island. At the high-frequency end of the spectrum are the semi-diurnal and diurnal components of the astronomical tides. Also affecting sea-level elevation are atmospheric pressure and the temperature and salinity (hence density) of the ocean column.
Changes in atmospheric pressure cause sea-level changes on the order of up to about 30 cm, by what oceanographers call the “inverted barometer effect.” As a result, pressure changes, like tides, generate waves that migrate across the water table. Amplitudes of the resultant pressure-related water-table fluctuations diminish inland. However, owing to the relatively long period of the pressure-related fluctuations, their inland attenuation is far less than that of the hydraulically analogous tides. In fact, in Bermuda for example, the pressure-related water-table fluctuations completely dominate water-table statistics that reflect day-to-day changes in elevation.
Because a drop in pressure and corresponding rise in the water table accompanies passage of a storm front, which also brings a rainfall, there is commonly a coincidental, and very misleading, correlation between rainfalls and water-table rises. In island and coastal settings, non-tidal sea-level changes and their effect on the water table must be taken into account, if recharge is to be correctly evaluated from water-table data.