The aerodynamic drag coefficient (C_D) is conjectured to change (or remains almost uniform) with the horizontal wind speed (U) over a flexible (or fixed) surface element, which is represented with the surface roughness (z₀). This conjecture is tested for the near neutral atmospheric turbulence (i.e. when surface stability z/L is almost equal to 0, where z is the measurement height and L is Obukhov length) of monsoon and winter season at an on-slope and a ridge-top site in the Indian Himalaya, wherein the ridge-top site is associated with a higher degree of sensitivity to the roughness element and terrain attributes. This hypothesis is successfully verified for two conditions, (i) the monsoon period observations of ridge-top site are found to have higher z₀ due to vegetative growth than the winter period for flows having similar terrain signature, and (ii) the monsoon and winter period observations of on-slope site are noted to have similar z₀ for flows having signature of steep terrain. Subsequently, constants (i.e. a and b) of the power-law relationships between C_D and U (i.e. C_D = aU^b), as a function of z₀, are optimized. It is noted that the relationship between C_D and U has higher sensitivity towards the terrain slope than the vegetative growth.

据推测，空气阻力系数（C _D）在柔性（或固定）表面元件上随水平风速（U）变化（或保持几乎均匀），并以表面粗糙度（z ₀）表示。测试该猜想是否接近中性大气湍流（即，当表面稳定性z / L几乎等于0时，其中z是测量高度，L是印度喜马拉雅山坡上和山脊顶部站点的季风和冬季季节的奥布霍夫长度，其中山脊顶部站点对粗糙度元素和地形属性的敏感性更高。对于两个条件，该假设已得到成功验证：（i）由于具有相似的地形特征，与冬季相比，由于营养生长，脊顶站点的季风期观测到的z ₀较高，（ii）季风和对于斜坡特征明显的水流，冬季坡地观测值的z ₀相似。随后，C之间的幂律关系的常数（即a和b）_D和U（即C _D  =  aU ^b）根据z ₀进行优化。值得注意的是，与营养生长相比， C _D和U之间的关系对地形坡度的敏感性更高。