Modelling turbulent energy dissipation in the high-latitude mesosphere

The global numerical model of the Earth's thermosphere, ionosphere and protonosphere constructed at the Kaliningrad Observatory of IZMIRAN and Polar Geophysical Institute in Murmansk (Namgaladze et al., 1991), hereafter referred to as PGI97, is being extended to encompass modelling of the mesosphere. Here we report the first predictions of turbulent intensities in the height regime SO to 90 km. Recently, Hall (1997) reported estimates of the turbulent energy dissipation rate, epsilon, using the EISCAT VHF radar located in Northern Norway (69 degrees N, 19 degrees E), which has, in turn, been compared to in situ measurements. Thus initial testing of PGI97 has concentrated on the same region. The agreements between PGI97 and EISCAT results for summer and winter solstice mesospheres are good. The general seasonal variation has been investigated, again showing good agreement with the EISCAT results. However, when examining the average energy dissipation in the 80-90 km height regime, the model shows less variability than the observations. (C) 1998 Elsevier Science Ltd. All rights reserved.