Open AccessVelocity spectra and turbulence using direct detection lidar and comparison with thermosonde measurements
Author(s) -
Dors I.,
McHugh J. P.,
Jumper G. Y.,
Roadcap J.
Publication year - 2011
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010jd014606
Subject(s) - turbulence , lidar , physics , spectral line , doppler effect , altitude (triangle) , computational physics , meteorology , optics , geometry , mathematics , astronomy
Observations of turbulence have been performed in New Hampshire near Mount Washington using two independent instruments: a ground‐based direct detection Doppler lidar and a balloon‐borne thermosonde. The Doppler lidar measures a time series of the velocity component parallel to the laser beam for each altitude. Spectra of the velocity time series are determined using the Scargle technique. Turbulence levels are estimated from the spectra assuming Kolmogorov behavior. The thermosonde measures the temperature difference between two sensors spaced 1 m apart, computes a running RMS average, and then determines the temperature turbulence parameter, C T 2 , also assuming Kolmogoroff behavior. The results show that the strongest levels of turbulence exist in a Kelvin‐Helmholtz layer in the altitude range of 1.2 < z < 1.9 km. This layer shows a three‐tier structure consisting of a well‐mixed layer in the center with strong velocity fluctuations bounded on top and bottom by layers with strong temperature fluctuations.