LF Wind Measurements at Collm
At Collm Observatory (51.3N, 13E) of the Leipzig University from 1959 to 2008
winds at mesopause heights (80 - 10 km altitude) have been measured. The measurements
base on the total reflection of radio waves in the lower nighttime ionosphere
using commercial radio transmitters on three measuring paths (at present on
177, 225, and 270 kHz, additionally 261 kHz). Since 1959 the used frequencies
were changed several times due to the requirements of the respective radio
stations, but not for more than 10 kHz.
In the beginning the data evaluation was done manually. Until 1973 they
were automated. Since September 1982 the reflection (reference) heights, measured
on 177 kHz (until 31.1.1986: 179 kHz), are used to calculate monthly or half-monthly
profiles and from this height-time cross-sections of the wind field parameters.
The results were published in
monthly reports
and scientific papers since1960.
The estimated parameters are:
- half-hourly means of the horizontal wind (about 12-18 hours/day, depending from season; all three measuring paths, and the mean) and the reflection height
- mean monthly or half - monthly wind profiles between about 80 and 100 km altitude
- monthly mean winds near 90 km, but calculated reference without height estimation.See here for comparison.
- daily values of the horizontal prevailing wind and the semidiurnal tide at about 90 km altitude
- estimates of gravity wave variances
Some data may be downloaded from this site.
More are available on request.
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Comments and Critics: jacobi@rz.uni-leipzig.de
last modification: 4.12.2008