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Rarotonga Second Structure Function Experiment
June 14--24, 2003

Preliminary Analysis by Alexander and Eleanor Praskovsky
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Fig. 1	A map of the antenna array. Note that Rarotonga has four receivers. The extra receiver allows extra baselines to be formed which is advantageous for structure function analysis.
Fig. 2	The dots indicate height/times of valid FCA wind retrieval during a typical day. Note the data loss at low alitudes during nighttime hours.
Fig. 3	Percentage of retrieved wind values over the entire campaign obtained with FCA and structure function analysis. No data rejection criteria were applied in the structure function analysis (although we may ultimately decide that this is necessary or desirable).
Fig. 4	FCA (blue) and SFA (red) winds over a three day period at 80 km. At this height FCA is "as good as it gets."
Fig. 5	Same as Fig. 4, but for an extremely low height. FCA essentially fails all the time at this height. Nothing has been done to remove (notch out) sea clutter at this altitude, although it is likely to be the dominant signal.
Fig. 6	Same as Figures 4 and 5 but for the uppermost height. Note the extremely large scatter in FCA as compared to SFA. We can use Rarotonga meteor winds for validation at this height (but have not yet done so).
Fig. 7	A more detailed look at SFA winds during a single day. The yellow envelope shows errors calculated using the distribution of wind estimates calculated from the multiple radar baselines. If you look carefully you will see that the SFA wind retrievals are irregular in time. There are repeated short gaps due to gaps in the recorded raw data. This is a flaw in the experiment that we hope to rectify in future experiments.
Fig. 8	Another example like Fig. 7, but for a different height and day.
Fig. 9	Scatter plot of FCA winds versus SFA winds.
Fig. 10	Time/height contours of the horizontal winds during a particular day.
Fig 11.	Same as Fig. 10, but for a different day.
Fig. 12	Vertical profiles of horizontal wind and turbulence parameters obtained with no temporal averaging. A unning averaging over 3 gates was applied.
Fig. 13	Same as Fig. 12, but for a different time.
Fig. 14	Power spectra of horizontal winds at 82 km, a height with high S/N. The lower panels show the residual after subtracting a fit to the spectra.
Fig. 15	Same as Fig. 14, but for a low altitude.
Fig. 16	Same as Fig. 14 and 15, but for the uppermost height.
Fig. 17	Turbulence parameters for a gate with high S/N (80 km). For this figure (as well as Figures 18 and 19) a classic Reynolds decomposition was applied to separate the instantaneous speed of a scattering medium (more exactly, of each scatterer) into the mean and turbulent components. Therefore, all fluctuations with respect to the mean over 102.4 s period were treated as turbulence independent of their real physical nature, e.g., gravity and other waves. The large values of \sigma_w, \sigma_u, and \sigma_v may be mainly from waves rather than small-scale turbulence.
Fig. 18	Same as Figure 14, but for a low altitude gate.
Fig. 19	Same as Figures 17 and 18, but for the uppermost gate.
Fig. 20	Height/time contour plots of the standard deviation of the horizontal turbulent velocities.