Polar cap mesosphere wind observations: comparisons of simultaneous measurements with a Fabry–Perot interferometer and a field-widened Michelson interferometer

Abstract

Polar cap mesospheric winds observed with a Fabry-Perot interferometer with a circle-to-line interferometer optical (FPI/CLIO) system have been compared with measurements from a field-widened Michelson interferometer optimized for E-region winds (ERWIN). Both instruments observed the Meinel OH emission emanating from the mesopause region (approximately 86 km) at Resolute Bay, Canada (74.9 degrees N, 94.9 degrees W). This is the first time, to our knowledge, that winds measured simultaneously from a ground-based Fabry-Perot interferometer and a ground-based Michelson interferometer have been compared at the same location. The FPI/CLIO and ERWIN instruments both have a capability for high temporal resolution (less than 10 min for a full scan in the four cardinal directions and the zenith). Statistical comparisons of hourly mean winds for both instruments by scatterplots show excellent agreement, indicating that the two optical techniques provide equivalent observations of mesopause winds. Small deviations in the measured wind can be ascribed to the different zenith angles used by the two instruments. The combined measurements illustrate the dominance of the 12-h wave in the mesopause winds at Resolute Bay, with additional evidence for strong gravity wave activity with much shorter periods (tens of minutes). Future operations of the two instruments will focus on observation of complementary emissions, providing a unique passive optical capability for the determination of neutral winds in the geomagnetic polar cap at various altitudes near the mesopause.

Correlations of mesospheric winds with subtle motion of the Arctic polar vortex

“…Accuracy of measurements is typically 1 m/s for a single observation, with an integration time of 1-2 s. A full set of measurements-zonal and meridional winds -takes about 20 min in the instrument configuration used for this paper. An excellent correlation was found in simultaneously measured wind velocities (corresponding to the ∼97 km green-line airglow emission) from ERWIN and a ground-based Fabry-Perot instrument (CLIO), also located at Resolute Bay (Fisher et al, 2000). Uninterrupted measurements are possible during darkness (polar winter) without significant cloud cover or bright moonlight within the instrument field-of-view.…”

Variability of atmospheric winds and waves in the Arctic polar mesosphere during a stratospheric sudden warming

“…The zero wind is determined from the average of the four cardinal directions. Comparisons of simultaneous measurements with a Fabry‐Perot interferometer (also stationed at Resolute Bay) and ERWIN have been done [ Fisher et al , 2000] and the two instruments are in excellent agreement.…”

Twelve‐hour tides in the winter northern polar mesosphere and lower thermosphere

“… Fisher et al [1999] presented the first FPI/CLIO mesopause wind results above Resolute. Fisher et al [2000] showed that both optical techniques provide equivalent observations of the mesopause winds at Resolute.…”

“…Observations at the northern polar latitudes are sparse due to the lack of ground‐based instruments at suitable sites and appropriately‐instrumented satellites with high orbital inclination. There exist only a few works that address the dynamics of the neutral MLT in the northern polar region—research has focused on observations at Resolute (74.9°N, 94.9°W) [ Fisher et al , 1999, 2000] and Eureka (80°N, 85°W) [ Sivjee et al , 1994; Oznovich et al , 1995; Walterscheid and Sivjee , 1996; Oznovich et al , 1997].…”