First Wind Measurements from a Fabry-Perot Interferometer at Bohyunsan Optical Astronomy Observatory, Korea
Abstract
We present the first measurements from a Fabry-Perot interferometer (FPI) installed at Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. The instrument, referred to as BHO-FPI, has been operated by the Korea Astronomy and Space Science Institute (KASI) since January 2025. BHO-FPI observes OI 557.7 nm, OI 630.0 nm, and OH 892.0 nm airglow emissions to estimate nighttime neutral winds from Doppler shifts in interference ring patterns. We describe the instrument configuration, data quality information, and initial wind observations from January 2025 to March 2026. The OI 630.0 nm observations, made along inclined lines of sight toward thermospheric altitudes, show seasonal variability in wind magnitudes, directions, and errors. Large wind errors occur mainly during summer, and they are likely associated with cloudy or rainy conditions. Because the cloud sensor sometimes misclassifies sky conditions, wind error values should be considered together with quality flags when BHO-FPI data are used. We also compare BHO-FPI winds derived from OI 557.7 nm airglow with KASI meteor radar winds at 94 and 96 km during clear nights in March 2025. Although the two instruments do not measure identical wind fields due to differences in site conditions and sampling volumes, the regression results show that BHO-FPI winds generally represent neutral winds near 96 km. During the G4-level geomagnetic storm on 19 January 2026, BHO-FPI observed clear reversals in both meridional and zonal winds in the thermospheric altitudes, indicating strongly southward and westward during the storm main phase. Similar wind changes during the geomagnetic storm were also observed by the Lowell-FPI (geographic latitude: 34.75°N, geographic longitude: 248.57°E). These initial results demonstrate that BHO-FPI can reliably monitor thermospheric winds over the Korean Peninsula and can support future studies of regional upper atmospheric dynamics and space weather effects.