The Eureka (80N,86W) meteor radar was originally installed as part
of the Canadian Network for the Detection of Atmospheric Change ( CANDAC )
led by Jim Drummond, now at Dalhousie University. By various nefarious
means it was kept in operation beyond the end of the funded 5 years,
until a less-well-funded collaboration, CCAR/PAHA (Climate Change
and Atmospheric Research / Probing of the Atmosphere of the High Arctic,
Due to serious interference from a nearby Star Photometer installed
in the fall of 2010, which despite much effort could not be reduced,
there was a major loss of winter data while it ran. Since the first
incident of extra noise (not Star Photometer), a sparse archive of
interim meteor signal files has been maintained which is processed to
yield noise levels during each day at each receiving antenna. The bad
intervals have been cut out before plotting the data presented here.
The radar is a semi-commercial SKiYMET (Wayne Hocking University of
Western Ontario, and Genesis Software Pty. Ltd., Australia )
Unfortunately the Tx failed in fall 2013 - and is taking a long time
for Genesis to fix. Still not in operation April 2015! But it's now back
running in another location starting September 2015 (with some ambient
temperature control problems!)
Just for pretty - here is an animation of real meteor postions, and their
horizontal components of speed, in a 90 minute fit interval
slid by 10 min, and the resulting wind fits
(takes a few seconds to load). The general clockwise rotation is caused by
atmospheric tides (due to solar heating, not gravitation).
The chosen January interval covers the yearly, very active but
short duration, Quadrantids meteor shower, Jan 3/4.
And finally, usually the major components of the daily wind are background
mean, diurnal (24 hr), and semi-diurnal (12hr) tidal oscillations ,
with seasonally constant hours of maximum. That is, for intervals of days
we expect to see a virtually constant wind at each hour and height.
Well - reality is different. The tidal phases can get pushed around, and
there are multi-day large scale waves, particularly in winter. To
illustrate, we show an animation
of a day. Data have been stretched by interpolating the hourly
means between days to simulate a 0.2 day step, resulting in a view Franz
Mesmer might have appreciated.
[ On Oct. 23,2016 one of the receiving antennas became twisted by ~40 deg.,
discovered by Wayne Hocking, who noticed the problem in monitor plots
just after it occurred
and joined a trip to Eureka in July 2017 to investigate (and also to
perform maintenance on his VHF radar).
The cause remains unknown. This interval covers 9 months of data.
Since raw data are not kept - though I do download a sparse
selection to keep track of external noise - it is not possible to
simply untwist the resulting meteor parameters. Several correction
methods are described:
Final method .]