第一次* *全球海平面测量通常是相对于当前的海平面在古气候研究* * *是*绝对测量,通常海面升降海水的(体积)。记住海平面是不同的在地球的表面,当测量从地球的中心由于自旋和重力异常所以没有绝对的高度,所以体积。海平面的相对措施,但这是指海洋深度比别的,因此是地方的影响。第二如果你没有猜到,* *海洋的体积不是常数* *它改变了不少,体积的水的体积和被占领。质量更加稳定(测量的规模),但即使这样的影响通过删除或添加水。海平面的许多措施* *海面升降的* *,这意味着他们是海洋测量的体积变化。* *在全球层面上有两大问题影响海平面,可用温度和水* *(主要是冰帽)。由于热膨胀的温度有很大影响,改变温度和水的体积变化即使质量是一样的。大多数的我们当前的海平面上升是由于热膨胀不融化的冰川。第二个是如果有冰盖和他们有多大,因为冰冻结在陆地上不是在海洋中。 The earth right now basically has only one ice cap (antarctica). Icecaps are largely controlled by whether their are continents near the poles. Isolated dry basins that flood can have a similar effect by increasing the area that needs to be filled, for instance when the mediterranean flooded it is [estimated][1] to have dropped global sea level (of the rest of the ocean) by ~ 9 meters in a about a year or two, which may be one of the most dramatic change in history, and probably scared the crap out of the humans around at the time. The drop is caused by increasing the volume being filled without changing the volume of water. There are lots of smaller and/or local effects that can change sea level or local sea level and wiki has a decent chart of them [here][2], these include age of the oceanic plates, plate rebound, and intercontinental reservoirs. [1]: http://www.nature.com/nature/journal/v462/n7274/full/nature08555.html [2]: https://en.wikipedia.org/wiki/Past_sea_level