LONG-TERM TEMPERATURE TRENDS IN THE MIDDLE AND UPPER-ATMOSPHERE

We analyse data from weekly rocket temperature soundings up to 75 km c arried out since mid - 1960s at polar (Heiss Island 80.6 degrees N and Molodezhnaya, 67.7 degrees S), temperate (Volgograd, 48.7 degrees N a nd Balkhash, 46.8 degrees N) and tropical (Thumba, 8.5 degrees N) lati tudes. All records show significant cooling which is of the order of a few degrees K at 30-40 km, 10 K at 50 km and 20 K at 60-70 km. In the mesosphere the temperature trends are estimated from the hydroxyl rot ational temperature records which start in 1957 at Zvenigorod (55.7 de grees N) and Abastumani (41.8 degrees N). These are related to the mes opause at 87 km and also show a cooling of about 30 K during the time. The cooling is qualitatively consistent with increasing concentration of greenhouse gases but may also reflect the changing chemistry of st ratosphere and mesosphere, which is clearly seen in increasing emissio n intensities of hydroxyl during the lab decades. Therefore the strato sphere and mesosphere may be regions with the strongest signals of glo bal change.