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(IVAR) - Final Report - Strategic Environmental Research and ...

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There are obvious gaps in the data collection seen in Figure 6-78. These gaps occurred because<br />

the SEAAR2l radar is installed on the rooftop of a building at SEA <strong>and</strong> radar operations were<br />

occasionally interrupted for reasons beyond our control, including: construction, regular<br />

maintenance in the vicinity of the radar, network <strong>and</strong> power outages, <strong>and</strong> other unforeseen events<br />

affecting system operation.<br />

Figure 6-78 demonstrates both the distribution of both short-term (daily) <strong>and</strong> longer-term<br />

(seasonal) changes in abundance of targets for one year at SEA. Obviously, one would require<br />

even longer timelines for comparison of seasonal activity from year-to-year in order to look for<br />

longer term trends in these activity patterns.<br />

From the full-year dataset, we selected the following three 5-day periods:<br />

• 12/1/2008 – 12/5/2008<br />

• 4/13/2009 – 4/17/2009<br />

• 9/21/2009 – 9/25/2009<br />

We then plotted hourly track counts for these three time periods. The selected dates are<br />

highlighted in red in Figure 6-79.<br />

We selected these three time periods arbitrarily, based only on the condition that they did not<br />

include extended outages in radar operations. Figure 6-80, Figure 6-81, <strong>and</strong> Figure 6-82,<br />

respectively plot the hourly track counts for these three time periods.<br />

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