Instruments:adf

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Adelaide MF Radar

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Acknowledgments

The Adelaide MF radar is operated by the Atmospheric Physics Group of the University of Adelaide, with support from the Australian Research Council. It contributes data as part of the joint TIMED-CEDAR program of the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF).

Instrument/Model Description:

The Adelaide, Australia (34.56S, 138.48E; ~19 m alt) 1.98 MHz MF radar has been in operation since 1983 at the location of Buckingham Park, just outside of Adelaide. On day 359 of 2001 at 89 km altitude, the apex magnetic coordinates were (28.2,-149.8) degrees. The magnetic inclination and declination angles were 48.0 deg and -6.4 deg. The magnetic local time at 0 Universal Time (UT) is about 0856 MLT. The solar local time (SLT) is UT plus 9 hours and 14 minutes (138.48/15.=9.232). Code 42 (LST-UT) was corrected from 1.E-03 hr to hhmm in Sep 2004.

The original data files are hourly averages of the zonal and meridional velocity in Australian Central Standard Time (ACST), which is 9 hr 30 min later than UT. Samples are taken every 2 min, so a possible 30 samples can be had between ACST 9:00:00 and ACST 9:59:00, which is labelled as hour 9:00:00 ACST. The midpoint is 9:30:00 ACST or 0:00:00 UT, or 9:14:00 SLT. Local times have been converted to the mid-point SLT, or 14 min (0.232 hr) are added to the begin LT.

The MF operating frequency is 1.98 MHz, with a peak transmitter power of 25 kW, 50 kW starting in 1995. The radar operates as a spaced-antenna system (Vincent, 1986), relying on coherent echo signals from middle atmosphere ionization. The inter-pulse period is 12.5 and 25 millisec, respectively during the day and night. There are usually 32 coherent integrations during the day and 16 at night, using 256 samples in the full correlation analysis (FCA) of Briggs [1984] with built-in rejection criteria. [ie, want about 2 min or 102.4 sec integration day or night, or 12.5x10-3sec * 32 integ * 256 samples = 102.4 sec and 25x10-3sec * 16 integ * 256 samples = 102.4 sec.]

The height coverage is 50-98 km during the day and 70-98 km during the night, at Adelaide. The pulse width is 30 microsec, giving a height resolution of 4.5 km assuming a simple rectangular wave pulse [range of heights illuminated by the wave pulse = velocity of light * pulse-width / 2 = 3x10**8 m/s * 30x10-6s / 2 = 4.5 km]. However, the height range provided is every 2 km between 60 and 98 km.

Starting in 2002, the data are also contributed to the joint TIMED-CEDAR program of the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF). The original hourly velocities are converted to harmonic analyses in UT over sliding 4-day intervals. The Mesosphere-Lower Thermosphere Radars (MLTR) organized for the TIMED-CEDAR program provide horizontal and sometimes 'vertical' neutral winds to the processing center at the University of Colorado. Summary plots from several types of MLTRs in the TIMED-CEDAR program and references for the instruments, analyses using the radars, and comparisons with other satellite or ground-based instruments can be found here

The harmonic analyses are also available at that site, or from the University of Colorado at:
http://sisko.colorado.edu/TIMED/data/MLTR/

Earlier results from the Adelaide MF radar in the CEDAR Database are harmonic analyses for LTCS 1-4 (1987-1990) campaigns using kindat=17999. These are the analyzed data on the neutral winds in the mesosphere and lower thermosphere during or including the LTCS-1 period, 21-25 September 1987. This condensed format is consistent with the analyzed data from other sites as well, and is prepared in order to facilitate research work. However, users need to inform the data suppliers that they are using the data in case of updates or changes, and to insure that the data are being used and interpreted properly.

The Adelaide MF radar employs the "spaced antenna" method. Tidal analysis is generally over 4 days, but monthly means are not simple arithmetic means, but are complex means. Observations are made relative to local time, which is 9.5 hours ahead of UT. The mean solar local time (SLT) is about 9 hours and 14 min ahead of UT. Thus, the phases have been converted to SLT by subtracting 0.3 hours from the phases in local time. The Adelaide radar has contributed extensively to middle atmosphere dynamical studies.

References

Briggs, B. H., The analysis of spaced sensor records by correlation techniques, MAP Handbook, Vol. 13, 166-186, 1984.
Fraser, G., Partial reflection spaced antenna wind measurements, MAP Handbook, Vol. 13, p 233, 1984.
A. H. Manson, C. E. Meek, and R. A. Vincent, Comparison between referenced atmosphere winds and radar winds from selected locations, Adv. Space Res., Vol 10, No. 12, pp 233-244, 1990.
A. H. Manson, C. E. Meek, R. Schminder, D. Kurschner, R. R. Clark, H. G. Muller, R. A. Vincent, A. Phillips, G. J. Fraser, W. Singer, and E. S. Kazimirovsky, Tidal winds from the MLT global radar network during the first LTCS campaign -- September 1987, J. Atmos. Terr. Phys., 52, pp 175-183, 1990.
A. H. Manson, C. E. Meek, E. Fleming, S. Chandra, R. A. Vincent, A. Phillips, S. K. Avery, G. J. Fraser, M. J. Smith, J. L. Fellous, and M. Massebeuf, Comparisons between satellite-derived gradient winds and radar-derived winds from the CIRA-86, J. Atmos. Sci., 48, pp 411-428, 1991.
A. H. Manson, C. E. Meek, S. K. Avery, G. J. Fraser, R. A. Vincent, A. Phillips, R. R. Clark, R. Schminder, D. Kurschner, and E. S. Kazimirovsky, Tidal winds from the mesosphere, lower thermosphere global radar network during the second LTCS campaign: December 1988, J. Geophys. Res., 96, pp 1117-1127, 1991.
A. Phillips and R. A. Vincent, Radar observations of prevailing winds and waves in the southern hemisphere mesosphere and lower thermosphere, Pure and Applied Geophys., 130, pp 303-318, 1989.
R. A. Vincent, T. Tsuda and S. Kato, Asymmetries in mesospheric tidal structure, J. Atmos. Terr. Phys., 51, pp 609-616, 1989.
Vincent, R. A., Hardware requirements: A new generation partial reflection radar for studies of the equatorial mesosphere, MAP Handbook, Vol. 20, p 85, 1986.
Vincent, R. A. and D. Lesicar, Dynamics of the equatorial mesosphere: First results with a new generation partial reflection radar, Geophys. Res. Lett., 18, 825-828, 1991.

LTCS 1-4 Harmonic Analyses Plots for Adelaide MF Radar

Summary Plots of Hourly Winds for TIMED from Adelaide MF Radar


-Revised 27 Sep 2004 by Barbara Emery