Abstract:
Rotational temperatures in the Mesosphere‐Lower Thermosphere region are estimated by
utilizing the OH(6,2) Meinel band nightglow data obtained with an Ebert‐Fastie spectrometer (EFS) operated at
Arecibo Observatory (AO), Puerto Rico (18.35°N, 66.75°W) during February‐April 2005. To validate the
estimated rotational temperatures, a comparison with temperatures obtained from a co‐located Potassium
Temperature Lidar (K‐Lidar) and overhead passes of the Sounding of the Atmosphere by Broadband Emission
Radiometry (SABER) instrument onboard NASA's Thermosphere Ionosphere Mesosphere Energetics and
Dynamics (TIMED) satellite is performed. Two types of weighting functions are applied to the K‐Lidar
temperature profiles to compare them with EFS temperatures. The first type has a fixed peak altitude and a fixed
full width at half maximum (FWHM) for the whole night. In the second type, the peak altitude and FWHM vary
with the local time. SABER measurements are utilized to estimate the OH(6,2) band peak altitudes and FWHMs
as a function of local time and considerable temporal variations are observed in both the parameters. The
average temperature differences between the EFS and K‐Lidar obtained with both types of weighting functions
are comparable with previously published results from different latitude‐longitude sectors. We found that the
temperature comparison improves when the time‐varying weighting functions are considered. Comparison
between EFS, K‐Lidar, and SABER temperatures reveal that on average, SABER temperatures are lower than
the other two instruments and K‐Lidar temperatures compare better with SABER in comparison to EFS. Such a
detailed study using the AO EFS data has not been carried out previously.
