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Interlude: Look at spectra from old data:
CWEX11:
Looking looking at 2 days (1&2 Aug) of spectra, see that noise amplitude is pretty constant, freq changes a small amount (~2.2 to 2.4 Hz), ncar2 is 2 orders of magnitude (in power -- 1 order of mag in amplitude) lower than ncar4. All of these are quite consistent.
Looking at 26 Jul (when I gave the tour), I recall that all turbines were stopped due to calm winds when I arrived (~13:00). During this period, the amplitude of the noise is about a factor of 2 smaller, though at the same frequency. Other hours of this day have noise levels similar to 1&2 Aug, though I have no information as to whether the turbines were running then.
Also, look at snapshots of data from other projects:
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