grade surface

• 坡面

grade surface的用法和样例：

例句

1. The fine grains are more at the tail than at the foreside at the same parallel to the slope surface.
   沿坡面方向，在离土面相同距离的位置，后部细颗粒多，前部细颗粒少。
2. The wetting front moved nearly parallel to the soil surface, and its length could be described by a power function of time, when the distribution of initial soil water was uniform.
   当初始含水量分布均匀时，降雨入渗过程中湿润锋面几乎平行坡面运移，湿润锋深度与时间的关系可用幂函数描述。