Comparison of Na Doppler lidar and MF radar measurements of meridional winds in the mesosphere above Urbana, IL

Simultaneous medium frequency (MF) radar and Na Doppler lidar measurements of meridional winds in the mesosphere (84-96 km) were collected at Urbana, IL in September and October, 1996. Comparisons on time scales of 1 h and lo nger and with height resolution of 3 km show that the two instruments measu re winds that agree to within tolerances established by statistical estimat ion errors at night. but reveal large differences that cannot be explained by estimation errors in the daytime. After removing the altitude-independen t component of both data sets, the wind estimates are shown to agree to wit hin expectations based on measurement uncertainty at all times of the day. The most likely explanation for differences between the two data sets is de termined to be undetected/uncorrected wavelength shifts in the lid ar, whic h would introduce offsets into the measured winds at all altitudes. (C) 200 1 Elsevier Science Ltd. All rights reserved.