The level of the ocean's surface, especially the level halfway between mean high and low tide, used as a standard in reckoning land elevation or sea depths.

海洋表面的水位，尤其是在平均高水位和低水位之间的平均位置的水位，用作计算陆地海拔和海水深度的标准。

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The generally accepted standard is 1020 watts per square meter at sea level.

普遍接受的标准1020在海平面每平方米瓦。

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The air pressure is also now closer to what is normal in Denver, Colorado -- the mile-high city at 5, 280ft -- than the traditionally higher, and more mountaintop-like standard of 8, 000ft above sea level, sparing fliers from the mild altitude sickness that can be experienced when flying a long distance.

BBC: Increased comfort in the sky