Meteor radar observations at middle and Arctic latitudes. Part 1: Mean temperatures

Observations with a Meteor radar operating at 32.55 MHz have been used to derive daily atmospheric temperature data for an altitude of 90 km at mid-latitudes during November 1999 until August 2001, and at high latitudes during September 2001 until December 2002. The neutral air temperatures are derived from determination of the ambipolar diffusion coefficient variation as a function of height, and are then corrected by application of a temperature-gradient model. The seasonal variations at both latitudes are characterized by high temperatures in winter and markedly smaller ones during summer. Whereas the winter temperatures at high latitudes are slightly warmer than at mid-latitudes by about 10 K, during summer the temperatures at high latitudes are colder by up to about 40 K. The majority of the variation in temperatures measured by this technique is due to variations in the ambipolar diffusion coefficient, but the accuracy of the temperature gradient model is important for second-order corrections. The meteor technique is valuable toot to study the short time temperature variability. The temperature data derived in this manner are in reasonable agreement with independent experimental results from different rocket, satellite and ground-based measurements, as well as with theoretical results obtained from calculations with the global circulation model COMMA-IAP.

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