above mean sea level

基本解释

With an elevation more than 3,659 meters (12,000 feet) above mean sea level, the Altiplano is much higher than the Chaco to the east.
Altiplano海拔3，659m(12,000英尺)，比亚热带区高多了。
IS the parenthetical figure following DH, DA or MDA which, when added to the touchdown zone, runway end, or threshold elevation, will give the DH, DA or MDA in feet above mean sea level.
决断高度或最低下降高度后括号中的数值。它与接地区、跑道顶端、或跑道头标高相加后即是决断高度（DA，DH）或最低下降高度（MDA）高于平均海平面英尺数。
The focal plane of the light is 200 feet above mean sea level, and in clear weather it should be seen at a distance of 23 nautical miles.
灯光的焦平面位于平均海平面以上200尺，如天气清朗，远至23海里的水域也能看见。