Analysis of Local Thermospheric Wind Patterns and Their Characteristics over the Korean Peninsula

The summer-to-winter pattern of neutral winds in the thermosphere is widely recognized as a global circulation mode. This mode is faithfully replicated by various wind models, including the Horizontal Wind Model (HWM14), which also simulate local thermospheric wind patterns. However, the investigation of these local patterns has been relatively sparse due to limitations in measurement techniques. The meteor radar operated by the Korea Astronomy and Space Science Institute (KASI-MR) measures neutral winds between 80 km and 100 km altitude. Meanwhile, the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI), onboard the NASA Ionospheric Connection Explorer (ICON), retrieves neutral winds at altitudes ranging approximately from 90 km to 300 km using the OI green line (557.7 nm). Utilizing these instruments, we conducted an analysis of the characteristics of local thermospheric winds over the Korean Peninsula. By combining KASI-MR and MIGHTI wind data, we produced extended local wind profiles spanning from December 2019 to November 2022. The monthly averaged diurnal winds exhibited considerable temporal variability, often exceeding ±150 m/s in both the zonal and meridional components. We also distinguished between the mid-to-upper thermospheric circulation and the lower-thermospheric circulation in the meridional winds. Moreover, the meridional wind profiles showed the switches of the direction with altitudes. However, the winds derived from HWM14 did not display distinct wind patterns in the meridional component. The findings of this study can be employed to validate general circulation models and provide input for numerical wave models.