Shoreline Position Prediction: Methods and Errors
Shoreline Position Prediction: Methods and Errors
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DOI：
10.1046/j.1526-0984.2000.71006.x
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发表时间：
2000-03
影响因子：
--
通讯作者：
Francis A. Galgano;B. Douglas
中科院分区：
文献类型：
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作者：
Francis A. Galgano;B. Douglas
海滩侵蚀是美国沿着普遍存在的问题。S.东海岸- 80-90%的海滩正在侵蚀。因此，联邦和州机构花费大量精力来确定侵蚀率，以建立施工后退线。历史海岸线位置被用来计算海滩宽度的变化率，但海岸线位置的时间变化造成了困难。在大多数高度发达或可能高度发达的地方，海滩侵蚀的年速率（1米量级）与海岸线位置测量的准确性（10米量级）或海滩宽度的季节至年际和更长时间的波动（数十米量级）相比是很小的。这种不利的信噪比使得确定潜在的长期侵蚀率的问题，即使是半个世纪长的海岸线位置记录，除非非常小心。做出有用的海岸线位置预测及其相关的错误，需要了解海岸线位置的时间变化的来源。我们使用了真实的海岸线位置数据的端点率（两个海岸线位置的差异除以时间）和线性回归分析，以证明几个美国东海岸线的问题的基本特征。在时间尺度<60-80年的情况下，计算的终点速率的离散度很大，任意的终点速率趋势既可能是侵蚀的，也可能是增生的，这表明不应使用终点速率方法。线性回归通常导致海岸线变化率的误差要小得多，但如果计算中包括受风暴影响的海岸线位置，则会导致预测位置的显著误差，特别是预测的不确定性。
Beach erosion is ubiquitous along the U. S. East Coast— 80–90% of the beaches are eroding. Federal and state agencies thus expend a great deal of effort to determine erosion rates for establishment of construction setback lines. Historical shoreline positions are used to calculate rates of change of beach width, but the temporal variability of shoreline position creates difficulties. In most places that are highly developed or likely to become so, the annual rate of beach erosion (order 1 meter) is small compared to the accuracy of shoreline position measurement (order 10 meters) or the seasonal-to-interannual and longer fluctuations of beach width (order tens of meters). This unfavorable signal-to-noise ratio makes determining the underlying long-term rate of erosion problematic from even half-century- long shoreline position records unless great care is taken. Making useful shoreline position predictions and their associated errors requires an understanding of the sources of temporal variability of shoreline position. We have used real shoreline position data in endpoint rate (difference of two shoreline positions divided by time) and linear regression analyses to demonstrate the essential features of the problem for several U.S. East Coast shorelines. The scatter in computed end point rates is so large at time scales <60–80 years that an arbitrary end point rate trend is as likely to be erosional as accretional, demonstrating that the end point rate method should not be used. Linear regression usually leads to much smaller errors in shoreline change rate, but significant errors in predicted position and especially the uncertainty of the prediction will result if storminfluenced shoreline positions are included in the computation.