Polar cap mesosphere wind observations: comparisons of simultaneous measurements with a Fabry-Perot interferometer and a field-widened Michelson interferometer
Gm. Fisher et al., Polar cap mesosphere wind observations: comparisons of simultaneous measurements with a Fabry-Perot interferometer and a field-widened Michelson interferometer, APPL OPTICS, 39(24), 2000, pp. 4284-4291
Polar cap mesospheric winds observed with a Fabry-Perot interferometer with
a circle-to-line interferometer optical (FPI/CLIO) system have been compar
ed with measurements from a field-widened Michelson interferometer optimize
d for E-region winds (ERWIN). Both instruments observed the Meinel OH emiss
ion emanating from the mesopause region (similar to 86 km) at Resolute Bay,
Canada (74.9 degrees N, 94.9 degrees W). This is the first time, to our kn
owledge, that winds measured simultaneously from a ground based Fabry-Perct
interferometer and a ground-based Michelson interferometer have been compa
red at the same location. The FPI/CLIO and ERWIN instruments both have a ca
pability for high temporal resolution (less than 10 min for a full scan in
the four cardinal directions and the zenith). Statistical comparisons of ho
urly mean winds for both instruments by scatterplots show excellent agreeme
nt, indicating that the two optical techniques provide equivalent observati
ons of mesopause winds. Small deviations in the measured wind can be ascrib
ed to the different zenith angles used by the two instruments. The combined
measurements illustrate the dominance of the 12-h wave in the mesopause wi
nds at Resolute Bay, with additional evidence for strong gravity wave activ
ity with much shorter periods (tens of minutes). Future operations of the t
wo instruments will focus on observation of complementary emissions, provid
ing a unique passive optical capability for the determination of neutral wi
nds in the geomagnetic polar cap at various altitudes near the mesopause. (
C) 2000 Optical Society of America OCIS codes: 010.1290, 120.3180, 120.2230
, 120.4640.