Millimetric Astronomy from the High Antarctic Plateau: site testing at Dome C
Valenziano L. , Dall'Oglio G., PASA, 16 (2), in press.

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AWS data analysis

**Figure 1:** Monthly averaged temperature at DC (upper panel) and SP (lower panel). The correlation between the two data sets is 96%.
$\begin{figure} \begin{center} \psfig{file=monthly_t.plt,angle=90,height=8cm} \end{center}\end{figure}$

AWS data used in this work are already binned in 3 hour intervals. This is useful in order to evaluate the stability of the observing conditions over a reasonably short interval. Some data can be missing, due to instrumental or transmission failures. Data were further averaged in one month intervals. The typical uncertainty in the monthly averages is 15% (standard deviation) for temperature, 1-6% for pressure and 50-75% for wind speed. Plots of these data are shown in Figures 1,3 and 5. Statistical distributions of the whole data set have also been calculated. Data have been binned in 1 $^{\circ }$ intervals for temperature, 1 hPa for pressure, 1 m/s for wind speed and 10 $^{\circ }$ for wind azimuth. Histograms for temperature, pressure, wind azimuth and wind speed are presented in Figures 2,4,6 and 7. Monthly plots of the whole data set and data distributions, along with a table with median values and mean absolute deviation, are reported elsewhere (Valenziano 1997).

**Figure 3:** Average pressure for DC (upper panel) and SP (lower panel). The correlation between the two data sets is 92%.
**Figure 2:** Temperature distributions for DC (continuous line) and SP (dotted line). The two distributions are consistent within errors. Median temperature is -53 $^{\circ }$ C. Data considered, over eight years, are 22596 for DC and 20814 for SP.
$\begin{figure} \begin{center} \psfig{file=t_cumul.plt,angle=90,height=8.5cm} \psfig{file=monthly_p.plt,angle=90,height=8.5cm}\end{center}\end{figure}$

**Figure 4:** Pressure distributions for DC (continuous line) and SP (dotted line). Median values are 644 hPa (22600 data) and 682 hPa (20808 data), respectively.
**Figure 5:** Average wind speed for DC (upper panel) and SP (lower panel). Correlation between data sets is less than 30%.
$\begin{figure} \begin{center} \psfig{file=p_cumul.plt,angle=90,height=8.5cm} \psfig{file=monthly_ws.plt,angle=90,height=8.5cm}\end{center}\end{figure}$

**Figure 6:** Wind azimuth distributions for DC (continuous line) and SP (dotted line). The distribution for DC (23034 points) is peaked around azimuth 180, while SP data (20784) are more uniformly distributed between azimuth 0 and azimuth 100.
**Figure 7:** Histogram of data, with cumulative distribution of wind speed over-plotted, for DC (continuous line) and SP (dashed line). Number of data considered is 23038 and 20782, respectively. Distributions are not symmetric. The 50th percentile (0.5 cumulative probability of measuring lower values) is 1 m/s for DC and 2 m/s for SP.
$\begin{figure} \begin{center} \psfig{file=wd_cumul.plt,angle=90,height=8.5cm} \par\psfig{file=ws_cumul.plt,angle=90,height=8.5cm} \end{center} \end{figure}$

Next Section: Precipitable Water Vapor measurements
Title/Abstract Page: Millimetric Astronomy from the
Previous Section: Automatic Weather Stations
Contents Page: Volume 16, Number 2

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AWS data analysis