Recent relative sea-level trends: an attempt to quantify the forcing factors
Recent relative sea-level trends: an attempt to quantify the forcing factors
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最近的相对海平面趋势：尝试量化强迫因素
DOI：
10.1098/rsta.2006.1739
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
H. Plag
中科院分区：
文献类型：
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作者：
H. Plag
当地的海平面受到许多强迫因素的影响，这些因素都有助于验潮仪观察到的趋势。在这里，我们使用的指纹的主要因素，有助于长期海平面的趋势，构建一个初始的经验模型，最好的解释海平面的趋势，记录了大量的沿海验潮站在过去的50年。考虑的强迫因素包括来自观测的空间变化，地球物理模型预测的冰后反弹，以及静态海平面方程预测的格陵兰和南极冰盖的质量变化。通过一个基于主要强迫因素空间指纹的模型对观测到的海平面趋势空间模式进行近似，充分利用了现有观测和模型的信息内容，并可在验潮站之间对海平面趋势进行插值。因此，我们得到的海平面趋势的全球图片，由于在分析中占的强迫因素。此外，我们推导出大冰盖的质量变化的约束。经验模型解释了海平面趋势变化的15%。然而，模型与观测值在0.38 ± 0.07的水平上相关，表明大部分无法解释的方差是由于小空间尺度的贡献。过去50年的平均结果表明，南极和格陵兰冰盖一直在融化，对全球海平面上升的贡献分别为0.39 ± 0.11和0.10 ± 0.05毫米。 从观测中得到的空间信号在海平面趋势中得到了清楚的识别，并且发现最小值为0.2 mm yr-1，最可能的值接近0.35 mm yr-1。 全球验潮站网络只覆盖了海洋表面的一小部分，但似乎感觉到海平面的平均上升幅度大于全球平均水平。将回归模型外推到全球海洋，并考虑到外推的不确定性，最有可能的全球平均值为1.05 ± 0.75毫米/年。
Local sea-level is affected by a number of forcing factors, which all contribute to the trends observed by tide gauges. Here we use the fingerprints of main factors contributing to secular sea-level trends to construct an initial empirical model that explains best the trends in sea-level as recorded by the large number of coastal tide gauges over the last 50 years. The forcing factors considered include steric changes derived from observations, post-glacial rebound as predicted by geophysical models and mass changes in the Greenland and Antarctic ice sheets as predicted by the static sea-level equation. The approximation of the observed spatial pattern of sea-level trends through a model based on the spatial fingerprints of the main forcing factors fully utilizes the information contents of the available observations and models and allows the interpolation of the sea-level trends between the tide gauges. As a result, we obtain the global picture of sea-level trends due to the forcing factors accounted for in the analysis. Moreover, we derive constraints on the mass changes of the large ice sheets. The empirical models explain about 15% of the variance of the sea-level trends. Nevertheless, the models are correlated with the observations on the level of 0.38±0.07, indicating that most of the unexplained variance is due to contributions with small spatial scales. Averaged over the last five decades, the results indicate that the Antarctic and Greenland ice sheets have been melting with an equivalent contribution to global sea-level rise of 0.39±0.11 and 0.10±0.05 mm yr−1, respectively. The steric signal derived from observations is clearly identified in the sea-level trends and is found to be at a minimum of 0.2 mm yr−1, with the most likely value being close to 0.35 mm yr−1. The global tide gauge network, which covers only a small fraction of the ocean surface, appears to sense an average sea-level rise larger than the global average. Extrapolating the regression models to the global ocean and taking into account the uncertainties in the extrapolation results in a most likely global average of the order of 1.05±0.75 mm yr−1.