Timed:Michelson Interferometers

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GBI Michelson Interferometers for TIMED

The basic geophysical output of Michelson Interferometers (MIs) is the neutral temperature at the peak of the [OH] layer, which is about 87 km. Clouds are not a big problem for temperature measurements, so there are temperature values approximately every 2-10 minutes for most of the periods of darkness.

G. G. Sivjee (sivjee@db.erau.edu) of Embry-Riddle Aeronautical University is responsible for the analysis of 6 of the 7 MIs, while Gary Swenson (swenson1@uiuc.edu) of the University of Illinois is responsible for the analysis of the MI at Socorro.

The MIs use a spectrum between about 2000-1000 nm (5000-10,000 cm-1 in wavenumber) where there are several hydroxyl Meinel (OH-M) bands that emit around 87 km in airglow. The rotational temperature (T) of [OH], which is the same as the ambient temperature, and the band brightness (B) are found. The relationship between B and T can give information on tides or gravity waves in the region. The brightness is related to the air density. The absolute temperature can vary between OH-M bands if the theoretical Einstein coefficients are not well known, but the ratio of the temperature change over temperature, which is related to wave or tidal activity, is about the same for all bands. However, recent comparisons between lidar and Michelson temperatures show that the absolute temperature from the OH-M (3,1) band using Nelson et al. [1990] coefficients agrees well with the lidar temperature. See Resolute Bay for a complete description of the instruments.

Richard Walterscheid (richard.walterscheid@aero.org) and Doug Strickland (dstrick@cpi.com) are co-PIs with Abas Sivjee on the CEDAR/TIMED grant.

Site Lat Lon Type Kinst Contact

South Pole, Antarctica

-90.00 0.00 MI 5700 G. G. Sivjee

Daytona Beach, FL, USA

29.199 -81.05 MI 5720 G. G. Sivjee
Socorro, NM, USA 34.07 -106.92 MI 5730 G. Swenson

Sondrestrom, Greenland

66.99 -50.95 MI 5900 G. G. Sivjee

Resolute Bay, Canada

74.68 -94.90 MI 5950 G. G. Sivjee
Longyearbyen, Svalbard NO 78.15 16.05 MI 5960 G. G. Sivjee

Eureka, Canada

80.22 -86.18 MI 5980 G. G. Sivjee

--Revised 05 Mar 2004 by emery@ucar.edu