Davis Station 55MHz meteor radar detections and winds

Brief description

This dataset contains the characteristics of sporadic meteor detections at 55MHz above Davis, Antarctica and the wind speed and direction in the middle atmosphere derived from those detections.

The capability to make these measurements is an add-on to the Davis 55MHz MST radar which is used when experiment schedules allow. As such, the duration of operation in this mode has varied through the life of the instrument.

The Davis 55 MHz atmospheric radar can be run in a meteor detection mode by selecting an alternate set of transmitting and receiving antennas. These consist of a single circularly polarized transmitting antenna and five linear polarized receiving antennas arranged in a ‘Mills Cross’ configuration.

In meteor mode, circularly polarized pulses are transmitted at a high repetition rate and the received signal is sampled at ranges sensitive to returns from the altitude range of 80-110 km approximately. If a meteor trail is present in the antenna field of view, increases of power of duration less than are second can be detected. The range is calculated from the pulse transit time and the direction of arrival is inferred from the relative phases of the signals at each receive antenna. Data files with a ‘.met’ extension contain the analysed data products from these detections and these include:
Event start time – The time of the detection
Range – The distance from the radar to the meteor trail
SNR – The signal to noise ratio of the detection
Angle of arrival – The azimuth and zenith angles of the direction from the radar to the meteor trail
Decay time – The exponential decay time of the detected signal (and its error)
Diffusion coefficient – An inferred trail diffusion coefficient (and its error)
Radial velocity – The speed with which the trail was moving toward or away (positive) from the radar (and its error)
Phase differences – The mean phase differences for each pair combination of the five antennas.

If enough meteors are detected, it is possible to infer a horizontal wind field at the height of the detections. This is done my assuming the wind flows without divergence or convergence in the vicinity of the radar over a selected averaging interval. Horizontal and vertical components of the wind are derived in this way and stored with their heights. These data are stored in files with a ‘.vel’ extension.

Data collection began in 2003 and is ongoing within scheduling constraints.

Project History:
The operation of the Davis 55MHz meteor detection radar began with:
Project 2529 – ‘A Meteor Radar for Measuring Mesospheric and Lower Thermospheric Winds and Temperatures at Davis Station’. 2004/05 to 2008/09.

Technical History:
Summer 2002/03 – The 55MHz meteor antenna array was constructed as part of the MST radar installation using antennas, cabling and switching provided by ATRAD and the University of Adelaide.
Changes to the MST radar transmitter and beam steering unit since that time have not affected the 55MHz meteor detection operation.