Spatial variability of late Holocene and 20th century sea-level rise along the Atlantic coast of the United States
Spatial variability of late Holocene and 20th century sea-level rise along the Atlantic coast of the United States
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DOI：
10.1130/g30360a.1
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发表时间：
2009-12-01
期刊：
影响因子：
5.8
通讯作者：
Toernqvist, Torbjorn E.
中科院分区：
文献类型：
--
作者：
Engelhart, Simon E.;Horton, Benjamin P.;Toernqvist, Torbjorn E.
在前卫星时代全球海平面上升的准确估计提供了一个背景下，21（st）世纪的海平面预测，但验潮仪记录的使用是复杂的，由于冰川均衡调整（GIA）的陆地水平变化的贡献。我们已经建立了一个严格的质量控制数据库晚全新世海平面指数从美国。S.大西洋海岸，缅因州的沉降速率< 0.8 mm a（-1），特拉华州的沉降速率增加到1.7 mm a（-1），而南卡罗来纳州的沉降速率恢复到< 0.9 mm a（-1）。这种模式可以归因于由于劳伦泰德冰盖的消亡而正在进行的GIA。我们的数据使我们能够定义的几何形状相关联的崩溃冰前隆起的分辨率水平无法比拟的任何其他目前可用的方法。相应的相对海平面上升速率作为背景速率，未来的海平面上升必须叠加在其上。我们进一步利用地质数据从验潮仪记录中去除GIA分量，以估计美国大西洋海岸世纪平均海平面上升速率为1.8 +/- 0.2 mm a（-1），与全球平均值相似。然而，我们发现一个明显的空间趋势，在20（th）世纪海平面上升的速度，增加从缅因州到南卡罗来纳州。这是仅从观测数据中首次证明这一现象。我们认为这可能与格陵兰冰盖的融化和/或海洋空间效应有关。
Accurate estimates of global sea-level rise in the pre-satellite era provide a context for 21(st) century sea-level predictions, but the use of tide-gauge records is complicated by the contributions from changes in land level due to glacial isostatic adjustment (GIA). We have constructed a rigorous quality-controlled database of late Holocene sea-level indices from the U. S. Atlantic coast, exhibiting subsidence rates of < 0.8 mm a(-1) in Maine, increasing to rates of 1.7 mm a(-1) in Delaware, and a return to rates < 0.9 mm a(-1) in the Carolinas. This pattern can be attributed to ongoing GIA due to the demise of the Laurentide Ice Sheet. Our data allow us to define the geometry of the associated collapsing proglacial forebulge with a level of resolution unmatched by any other currently available method. The corresponding rates of relative sea-level rise serve as background rates on which future sea-level rise must be superimposed. We further employ the geological data to remove the GIA component from tide-gauge records to estimate a mean 20(th) century sea-level rise rate for the U.S. Atlantic coast of 1.8 +/- 0.2 mm a(-1), similar to the global average. However, we find a distinct spatial trend in the rate of 20(th) century sea-level rise, increasing from Maine to South Carolina. This is the first evidence of this phenomenon from observational data alone. We suggest this may be related to the melting of the Greenland ice sheet and/or ocean steric effects.