Abstract
Abstract. Long-term and continuous observations of mesospheric–lower thermospheric winds are rare, but they are important to investigate climatological changes at these altitudes on timescales of several years, covering a solar cycle and longer. Such long time series are a natural heritage of the mesosphere–lower thermosphere climate, and they are valuable to compare climate models or long-term runs of general circulation models (GCMs). Here we present a climatological comparison of wind observations from six meteor radars at two conjugate latitudes to validate the corresponding mean winds and atmospheric diurnal and semidiurnal tides from three GCMs, namely the Ground-to-Topside Model of Atmosphere and Ionosphere for Aeronomy (GAIA), the Whole Atmosphere Community Climate Model Extension (Specified Dynamics) (WACCM-X(SD)), and the Upper Atmosphere ICOsahedral Non-hydrostatic (UA-ICON) model. Our results indicate that there are interhemispheric differences in the seasonal characteristics of the diurnal and semidiurnal tide. There are also some differences in the mean wind climatologies of the models and the observations. Our results indicate that GAIA shows reasonable agreement with the meteor radar observations during the winter season, whereas WACCM-X(SD) shows better agreement with the radars for the hemispheric zonal summer wind reversal, which is more consistent with the meteor radar observations. The free-running UA-ICON tends to show similar winds and tides compared to WACCM-X(SD).
Highlights
For space weather applications, there is a growing need for climatological boundary conditions of winds and temperature at the mesosphere–lower thermosphere (MLT) for climatological means as well as to assess the day-to-day variability due to atmospheric waves (Liu, 2016)
We present a climatological comparison of MR winds and the corresponding GAIA, Whole Atmosphere Community Climate Model Extension (WACCM-X)(SD), and Upper Atmosphere ICOsahedral Non-hydrostatic (UA-ICON) fields for six meteor radars at conjugate middle and polar latitudes to investigate interhemispheric differences and to evaluate how well the observations and the general circulation models (GCMs) data show similar dynamics
We present observations from six meteor radars and derived climatologies from the continuous observations for the abovementioned meteorological parameters, which are cross-compared to nudged model simulations from GAIA and WACCMX(SD) for the same periods that the measurements are available from each radar
Summary
There is a growing need for climatological boundary conditions of winds and temperature at the mesosphere–lower thermosphere (MLT) for climatological means as well as to assess the day-to-day variability due to atmospheric waves (Liu, 2016). Cormack et al (2017) validated the MLT winds of a meteorological analysis obtained with the Navy Global Environmental Model – High Altitude (NAVGEM-HA) and data from globally distributed meteor radars (MRs) for two winter seasons. They found remarkably good agreement of the NAVGEM-HA winds and the MR observations even for timescales of days as well as for the tidal variability. We present a climatological comparison of MR winds and the corresponding GAIA, WACCM-X(SD), and UA-ICON fields for six meteor radars at conjugate middle and polar latitudes to investigate interhemispheric differences and to evaluate how well the observations and the GCM data show similar dynamics.
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