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Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures
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Magneto-optic Doppler analyzer: a new instrument to measure mesopause winds
Applied Optics
|December 4, 2010
Summary
The magneto-optic Doppler analyzer measures wind speeds using sodium nightglow. This instrument provides consistent horizontal wind data and reveals seasonal patterns of the semidiurnal tide.
Area of Science:
- Atmospheric physics
- Geophysics
- Optical instrumentation
Background:
- The mesopause region is crucial for understanding atmospheric dynamics.
- Measuring upper atmospheric winds requires specialized techniques.
- Sodium nightglow provides a remote sensing target for atmospheric studies.
Purpose of the Study:
- To introduce and validate the magneto-optic Doppler analyzer (MODA) for atmospheric wind measurements.
- To assess MODA's capability in measuring horizontal wind signatures from sodium nightglow.
- To demonstrate MODA's utility in long-term atmospheric studies.
Main Methods:
- Utilizing a passive optical instrument based on a sodium vapor magneto-optic filter.
- Measuring the Doppler shift of sodium nightglow emissions at ~91 km altitude.
- Inferred horizontal wind (zonal and meridional) from Doppler shift data.
- Continuous nightly measurements at Niwot Ridge, Colorado since 1994.
Main Results:
- Achieved inherent wavelength stability and low cost with the magneto-optic filter.
- Obtained internally consistent zonal and meridional wind measurements.
- Successfully measured the semidiurnal tide over several seasons.
- Demonstrated reliable nightly wind data acquisition since October 1994.
Conclusions:
- The magneto-optic Doppler analyzer is a cost-effective and stable instrument for mesopause wind measurements.
- MODA provides valuable data for studying atmospheric dynamics, including tidal oscillations.
- Long-term monitoring with MODA contributes to understanding seasonal wind variations in the upper atmosphere.
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