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海平面上升,或者地板上越来越高?

我随机蹦进我脑子里有一个问题:“为什么海洋咸,但河流不是吗?”

这篇文章似乎提供一个合理的解释:http://oceanservice.noaa.gov/facts/riversnotsalty.html

它基本上是说:

雨一直把淡水河流,这就是为什么他们不“咸”。
河流,流,从地上捡起沉积物,推动到海洋。这或多或少的沉积物,使海洋味道“咸”。

这让我我的问题:大海真的是“上升”,还是地上刚刚“厚/高”。本文指出,数百万吨的沉积物被沉积在海底。大多数人认为/相信冰川融化导致的海平面上升。我不想反驳说,但不能所有的沉积物是一个重要的因素吗?即。也许海洋水平并不像我们认为的“崛起”,但是,相反,沉积物的水变得流离失所?

回答

在一个地质静态的世界你可能有一个点。侵蚀磨损陆地表面,沉积在海洋沉积物——阿基米德原理的应用,和海洋水平将上升位移。有两个主要原因,这并不占海平面上升的速度,我们看到:板块构造和观察到的水平。地球是一个巨大的动态环境中地壳板块构造驱动一个近似平衡遭到破坏,水土流失和俯冲,对新生成的土地“建设性的利润”。这种“不稳定平衡”已经过去3 +几十亿年,并有可能继续达几十亿年之久。平均海平面的升降平衡接近于零,但积极的和消极的异常。在所有情况下,波动缓慢,在数百万年的顺序(不包括大得多的短期波动引起的冰河时代)。所以实际上基线是“零变化”,这是叠加的影响海平面上升我们退出最后一个冰河时代,即过去的12000年里,继续。最重要的是最近的人类活动造成了气候变化的影响。让我们考虑这些利率相比,假设的侵蚀率和海平面上升在一个静态的世界。 During the 20th century, sea level rise was estimated from tide-gauges, which raises the problem of 'are we measuring rising sea or sinking land?' For the last decade or so we have been able to measure absolute mean sea levels by satellite. That is, independent of land levels. Now we can re-evaluate old data, and come up with 'real' average rates of rising sea level. They turn out to be about 2.5 +/- 1.5 mm/year for most of the last century. Now they have accelerated to more than twice that amount. See, for example: https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level This is the *global average*, and yes, there are all manner of positive and negative anomalies. Now consider sediment displacement. Measuring the global sediment flux from rivers to oceans is extraordinarily difficult, for reasons which would take several pages to explain. But of the diverse range of estimates the consensus seems to be between 20 and 60 Gtonnes per year for the world's major rivers. Leaning towards the upper bound, and adding in a factor for the minor rivers, and assuming an average sediment density of about 2.5, we arrive at about 40 billion cubic metres of sediment entering the oceans each year. There are about 360 million square kilometres of ocean, so on average, the annual increase in ocean sediment is about 1.1 mm. In reality, this is an upper bound with the a more realistic estimate being about 0.6 mm. So, even without taking oceanic subduction into account, the observed sea level is at least an order of magnitude more than can be accounted for by sediment displacement. Or to answer your question, no, the ocean floor isn't rising at any rate that we can measure. Conversely, sea level *is* rising at a rate that is consistent with thermal expansion of the ocean surface, combined with nett global ice melt.

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\ begingroup美元是如何“2.5 + / - 1.5毫米/年”是“至少一个数量级”超过1.1毫米/年?这是一个特殊的“气候代数”吗?同时,海底是由构造板块的移动。为什么你的解释不占,海底就趋于平缓,和大陆只是堕落一点吗? \ endgroup美元
- - - - - -啤酒. . chenski
2016年11月19日在3:14

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