资源环境科技发展态势分析平台

Flow in rivers and the coastal ocean is controlled by the frictional force exerted on the water by riverbed or seabed roughness. The frictional force is typically characterized by a drag coefficient C_d, which is estimated from bulk measurements and often assumed constant. Here we demonstrate a relationship between bed roughness and water surface turbulence that can be used to make remote estimates of C_d. We observe that regions with larger bed roughness result in greater turbulent kinetic energy (TKE), which is transported upward by river boils to the water surface. We present a relationship between surface TKE and C_d, and validate this relationship by comparing remotely‐sensed estimates of C_d to those from in situ measurements. Thus, our results provide an approach for estimating bottom roughness and C_d based entirely on remotely sensed data, including their spatial variability, which can improve modeling of river discharge and morphodynamics in data‐poor regions.