ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-22-863-2004 Comparison of high-latitude thermospheric meridionalwinds II: combined FPI, radar and model Climatologies Griffin E. M. 1 Aruliah A. 1 Müller-Wodarg I. C. F. 1 Aylward A. 1 Atmospheric Physics Laboratory, University College London, 67-73 Riding House Street, London W1W 7EJ, UK 19 03 2004 22 3 863 876 Copyright: © 2004 E. M. Griffin et al. 2004 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/22/863/2004/angeo-22-863-2004.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/22/863/2004/angeo-22-863-2004.pdf

The climatological behaviour of the thermospheric meridional wind above Kiruna, Sweden (67.4°N, 20.4°E) has been investigated for seasonal and solar cycle dependence using six different techniques, comprising both model and experimental sources. Model output from both the empirical Horizontal Wind Model (HWM) (Hedin et al., 1988) and the numerical Coupled Thermosphere and Ionosphere Model (CTIM) are compared to the measured behaviour at Kiruna, as a single site example. The empirical International Reference Ionosphere (IRI) model is used as input to an implementation of servo theory, to provide another climatology combining empirical input with a theoretical framework. The experimental techniques have been introduced in a companion paper in this issue and provide climatologies from direct measurements, using Fabry-Perot Interferometers (FPI), together with 2 separate techniques applied to the European Incoherent Scatter radar (EISCAT) database to derive neutral winds. One of these techniques uses the same implementation of servo theory as has been used with the IRI model. Detailed comparisons for each season and solar activity category allow for conclusions to be drawn as to the major influences on the climatological behaviour of the wind at this latitude. Comparison of the incoherent scatter radar (ISR) derived neutral winds with FPI, empirical model and numerical model winds is important to our understanding and judgement of the validity of the techniques used to derive thermospheric wind databases. The comparisons also test model performance and indicate possible reasons for differences found between the models. In turn, the conclusions point to possible improvements in their formulation. In particular it is found that the empirical models are over-reliant on mid-latitude data in their formulation, and fail to provide accurate estimates of the winds at high-latitudes.<br><br> <b>Key words.</b> Meteorology and atmospheric dynamics (thermospheric dynamics), Ionosphere (ionosphere-atmosphere interactions, auroral ionosphere)