Since the distance from any given radar to each of these reflective surfaces (which may be as much as 50km, or 30 miles, away) is known precisely, the time it takes a beam to get there and back is a measure of how much water vapour it contains.
Since the distance from any given radar to each of these reflective surfaces (which may be as much as 50km, or 30 miles, away) is known precisely, the time it takes a beam to get there and back is a measure of how much water vapour it contains.
知道了从特定的雷达到可反射的表面的距离，波束到那达和返回所花费的时间就确定为一个衡量包含多少水蒸汽的尺度。