Studies of Mid-latitude Mesospheric Temperature Variability and Its Relationship to Gravity Waves, Tides, and Planetary Waves

• Main Author: Beissner, Kenneth C.
• Format: Text
• Language: unknown
• Published: Utah State University 1997
• Subjects: Norway; Andenes
• Online Access: https://dx.doi.org/10.26076/12c4-80ee; https://digitalcommons.usu.edu/etd/4687

Temperature observations of the middle atmosphere have been carried out from September 1993 through July 1995 using a Rayleigh backscatter lidar located at Utah State University (42°N, 111°W). Data have been analyzed to obtain absolute temperature profiles from 40 to 90 km. Various sources of error were reviewed in order to ensure the quality of the measurements. This included conducting a detailed examination of the data reduction procedure, integration methods, and averaging techniques. eliminating errors of 1-3%. The temperature structure climatology has been compared with several other mid-latitude data sets. including those from the French lidars, the SME spacecraft, the sodium lidars at Ft. Collins and Urbana, the MSISe90 model, and a high-latitude composite set from Andenes, Norway. In general, good agreement occurs at mid-latitudes, but areas of disagreement do exist. Among these, the Ctah temperatures are significantly warmer than the MSJSe90 temperatures above approximately 80 km, they are lower below 80 km than any of the others in summer, they show major year-to-year variability in the winter profiles, and they differ from the sodium lidar data at the altitudes where the temperature profiles should overlap. Also, comparisons between observations and a physics based global circulation model, the TIME-GCM, were conducted for a mid-latitude site. A photo-chemical model was developed to predict airglow intensity of OH based on output from the TIME-GCM. Many discrepancies between the model and observations were found , including a modeled summer mesopause too high , a stronger summer inversion not normally observed by lidar, a fall-spring asymmetry in the OH winds and lidar temperatures but not reproduced in the TIME-GCM equinoctial periods, larger winter seasonal wind tide than observed by the FPl, and a failure of the model to reverse the summenime mesospheric jet. It is our conclusion these discrepancies are due to a gravity wave parameterization in the model that is too weak and an increase will effectively align the model calculations with our observations.