| Popis: |
From Aug. 1993 to Feb. 1996, regular Rayleigh-scatter observations of the stratosphere and mesosphere in the altitude range 40–95 km were made with the Consortium Lidar (CL) located at Utah State University. These observations are now being continued with the Atmospheric Lidar Observatory (ALO) at the same location. The site is located at mid latitude in the middle of the Rocky Mountains—41.75° N, 111.80° W. Atmospheric density profiles derived from the lidar returns are reduced to temperature profiles, with considerable care being taken to avoid possible systematic errors. In summer months, the Utah mesospheric temperatures, like those from elsewhere, show the least variability and the expected monotonic decrease of temperature with altitude. However, the Utah temperatures appear systematically lower than others. Between spring and fall, an important feature of the temperature climatology is a strong asymmetry, which appears to be larger than elsewhere. In winter, day-to-day temperature variability is greatest, but variability also exists on the scale of a week. Perhaps as a consequence, or perhaps for another reason, the Utah data show an enormous change from one January to the next. Are these differences in the climatology real? If so, can they be related to the mountainous location and the orographic generation of gravity waves? Can the temporal variations be related to planetary (Rossby) waves and the generation of gravity waves by the jet stream? |
