Aerodynamic roughness as a function of wind direction over asymmetric surface elements
- Cite this article as:
- Jackson, B.S. & Carroll, J.J. Boundary-Layer Meteorol (1978) 14: 323. doi:10.1007/BF00121042
Wind speed and temperature profiles to a height of 8 m were recorded for 30-, 60-, and 90-min averaging times over a striated snow surface at the geographic South Pole during the austral winter of 1975. A gradient Richardson number was calculated for each averaging time to determine conditions of neutral stability under which the logarithmic wind law would hold. A log-linear regression technique was used to determine values of aerodynamic roughness height (Z0) for those profile averages recorded in conditions of neutral stability. A plot of Z0 as a function of average wind direction revealed a variation in Z0 of almost three orders of magnitude, from 0.01 to 7 cm, over 120 deg of wind direction. A simple model is presented to justify the fact that aerodynamic roughness is a function of wind direction and erosion history.