The wind profile of the atmospheric boundary layer ( surface to around 2000 metres ) is generally logarithmic in nature and is best approximated using the log wind profile equation that accounts for surface roughness and atmospheric stability.
12.
\sigma _ z and \ sigma _ y are functions of the atmospheric stability class ( i . e ., a measure of the turbulence in the ambient atmosphere ) and of the downwind distance to the receptor.
13.
The vertical range of sodars is approximately 0.2 to 2 kilometers ( km ) and is a function of frequency, power output, atmospheric stability, turbulence, and, most importantly, the pulse length and maximum altitude.
14.
The lack of heavy rainfall arises from high atmospheric stability caused, in turn, by the combination of cool waters from semi-permanent coastal upwelling and the presence of the cold Humboldt Current and warm air aloft associated with the South Pacific anticyclone.
