I shot the angles for the RMYoung sonics. I used a combination of a compass and the theodolite.
The compass was set with 0 degree deviation. When we get the new datascope I will take another set of readings.
The sonics were mounted with the N direction pointing toward the East.
| Height | 9/1 (SS) | 10/25 (KY and GM) | ||
|---|---|---|---|---|
| 10m | 81 | 76.5 | ||
| 25m | 82 | 76.5 (leans toward South) | ||
| 33m | 78 | 76 | ||
| 41.8m | 78 | 79 | ||
| 49m | 81 | 78 |
10/25/2016 - We found the compass on the Theolite was no good, based on comparisons with the binoculars. We used the Theolite to align the sonic and then used the binoculars to measure the angels.
4 Comments
Gordon Maclean
More on the 10/25 readings. These were take from the west side of Park Rd, north of the junction with the access road to the turbine.
Used the David White theodolite, attached with two "C" clamps to the large tripod. Moved it and leveled for each sonic, until the vertical cross-hair was lined up with the rear transducer array support and the middle of the black box at the bottom of the sonic tube. Since the compass on the theodolite seems to have a sticky needle, we then sighted on the tower with the binoculars, standing behind the theodolite and took readings from the binocular compass.
I believe this was a similar procedure to what was done on 9/1.
Gordon Maclean
Or notes indicate that the sonic leaning to the south was actually the 25m, not 33. However the tilt plots suggest that the 42m has the worst lean to the side (lean=5.1, leanaz=-66).
Gordon Maclean
Verified visually that the 25 is the one that leans toward the south. The tilt plot agrees, showing a lean of 3.7 deg, leanaz=4.5. The instrument coords of RMY's are rotated 90 degrees clock-wise relative to CSATs, so the tilt analysis agrees with the visual.
At 42 meter, a tilt angle of 5.1, leanaz=-66, means the sonic is leaning toward us when sighting with the threodolite.
Steve Oncley
Using https://www.ngdc.noaa.gov/geomag-web/, I find that the declination for this site is 11d 27' W (or ~11.5 deg). Thus, these angles for wind direction into the boom should be about 65 deg true. This value is consistent with my quick check of 69 deg using Google Earth (trying to remember where we shot the angles from).