After correction of the sonic orientations using the sonic boom angles measured with the Data Scope, there were still systematic differences in the sonic wind directions across the arrays that were broadly correlated with the post-project sonic zero wind offsets measured in the wind tunnel. Therefore we subtracted offset corrections from the sonic horizontal wind components u and v.
The offsets were determined by assuming that the time-averaged wind field was uniform across each sonic array. First the mean values of the horizontal wind components were calculated for each sonic over the period of each configuration (or sub-configuration), only using data with wind directions within 45 degrees of normal to the array and wind speeds exceeding 1 m/s. The wind offset corrections were then derived by selecting one or more reference sonics in each array with small post-project-measured offsets. These were sonic 8u (s/n 0673) in the upwind array, sonic 6t (0672) in the top array, and sonics 4b (0744), 5b (0745) and 6b (0376) in the bottom array. The u and v offsets for each sonic were calculated as the differences between its mean values for u and v and the mean values for the corresponding reference sonic. To these offsets were added the wind-tunnel offsets measured for the reference sonics. Note that this procedure does not account for the variation of sonic wind offsets with temperature, but simply removes the mean offset irrespective of temperature.
u offsets (cm/s) for upwind arrays wrt CSAT 8u + 4.4 cm/sec
Sonic \ Config |
1.1* |
1.51* |
1.52* |
2 |
3 |
4 |
|---|---|---|---|---|---|---|
3u |
2 |
8 |
11 |
14 |
13 |
13 |
4u |
-5 |
-7 |
-3 |
-4 |
-1 |
-3 |
5u |
-7 |
-3 |
-2 |
-2 |
-2 |
-1 |
6u |
10 |
16 |
16 |
18 |
21 |
15 |
7u |
-2 |
-6 |
-7 |
0 |
0 |
-3 |
8u |
4 |
4 |
4 |
4 |
4 |
4 |
9u |
-7 |
-3 |
-4 |
-3 |
0 |
-3 |
10u |
2 |
6 |
0 |
-4 |
-8 |
-12 |
11u |
-9 |
-5 |
1 |
3 |
9 |
3 |
* Configuration 1 was divided into sub-periods because of its length and the expectation that the offsets may have changed with time.
Config 1.1: June 25 12:00 to July 1 12:17 (upwind height = 3.74m)
Config 1.51: July 1 12:55 to July l 9 09:25 (upwind height = 3.24m)
Config 1.52: July 9 09:25 to July 18 05:55 (upwind height = 3.24m)
v offsets (cm/s) for upwind arrays wrt CSAT 8u + 3.3 cm/sec
Sonic \ Config |
1.1 |
1.51 |
1.52 |
2 |
3 |
4 |
|---|---|---|---|---|---|---|
3u |
7 |
-3 |
3 |
17 |
18 |
18 |
4u |
3 |
-6 |
-7 |
2 |
-3 |
-4 |
5u |
6 |
-1 |
3 |
20 |
17 |
14 |
6u |
17 |
21 |
24 |
24 |
19 |
19 |
7u |
5 |
-3 |
-8 |
2 |
-11 |
-7 |
8u |
3 |
3 |
3 |
3 |
3 |
3 |
9u |
11 |
7 |
7 |
16 |
11 |
14 |
10u |
7 |
3 |
1 |
1 |
2 |
4 |
11u |
20 |
23 |
22 |
19 |
18 |
22 |
u offsets for top arrays wrt CSAT 6t + 2.3 cm/sec
Sonic \ Config |
1.2* |
1.6* |
2 |
3 |
4 |
|---|---|---|---|---|---|
3t |
1 |
-1 |
-7 |
-16 |
-11 |
4t |
1 |
7 |
12 |
14 |
13 |
5t |
-1 |
5 |
6 |
3 |
2 |
6t |
2 |
2 |
2 |
2 |
2 |
7t |
-1 |
4 |
4 |
3 |
3 |
8t |
2 |
4 |
5 |
10 |
6 |
9t |
2 |
4 |
9 |
13 |
9 |
10t |
7 |
10 |
9 |
13 |
10 |
11t |
5 |
11 |
17 |
13 |
12 |
* Config 1.2: June 25 12:00 to July 6 12:00
Config 1.6: July 6 12:00 to July l8 05:55
v offsets for top arrays wrt CSAT 6t + 2.2 cm/sec
Sonic \ Config |
1.2 |
1.6 |
2 |
3 |
4 |
|---|---|---|---|---|---|
3t |
7 |
11 |
10 |
5 |
15 |
4t |
7 |
6 |
14 |
10 |
6 |
5t |
-23 |
-26 |
-6 |
2 |
0 |
6t |
2 |
2 |
2 |
2 |
2 |
7t |
-9 |
-14 |
-15 |
-17 |
-19 |
8t |
10 |
12 |
-1 |
-4 |
3 |
9t |
3 |
4 |
0 |
7 |
3 |
10t |
5 |
4 |
-4 |
-4 |
-5 |
11t |
1 |
0 |
-3 |
-3 |
-5 |
u offsets for bottom arrays wrt CSAT 4,5,6b + 1.33 cm/sec
Sonic \ Config |
1.2 |
1.6 |
2 |
3 |
4 |
|---|---|---|---|---|---|
1b |
10 |
12 |
21 |
7 |
8 |
2b |
2 |
0 |
18 |
13 |
12 |
3b |
6 |
6 |
6 |
9 |
2 |
4b |
5 |
5 |
1 |
3 |
2 |
5b |
0 |
0 |
-2 |
-2 |
0 |
6b |
-1 |
-1 |
5 |
3 |
2 |
7b |
9 |
9 |
5 |
6 |
5 |
8b |
2 |
3 |
-4 |
-3 |
-4 |
9b |
-12 |
14 |
-13 |
-6 |
-6 |
10b |
2 |
1 |
-2 |
-4 |
-14 |
11b |
0 |
5 |
5 |
2 |
0 |
12b |
16 |
23 |
26 |
19 |
15 |
13B |
3 |
12 |
11 |
2 |
0 |
v offsets for bottom arrays wrt CSAT 4,5,6b + 0.67 cm/sec
Sonic \ Config |
1.2 |
1.6 |
2 |
3 |
4 |
|---|---|---|---|---|---|
1b |
14 |
18 |
13 |
23 |
25 |
2b |
4 |
-4 |
-1 |
-3 |
4 |
3b |
-3 |
-6 |
-16 |
-13 |
-10 |
4b |
-14 |
-16 |
1 |
3 |
-1 |
5b |
-16 |
-15 |
3 |
2 |
5 |
6b |
32 |
34 |
-2 |
-4 |
-2 |
7b |
-8 |
-9 |
-13 |
-10 |
-9 |
8b |
-4 |
-2 |
-6 |
-6 |
-2 |
9b |
-2 |
8 |
2 |
5 |
10 |
10b |
5 |
16 |
10 |
10 |
14 |
11b |
1 |
-2 |
-8 |
-11 |
-11 |
12b |
3 |
0 |
-3 |
-8 |
-8 |
13b |
1 |
-4 |
-14 |
-19 |
-2 |
We intend to estimate advection by taking the differences between data from the upwind sonic array and data from the downwind, bottom array. Therefore I have calculated the height difference between the sonic measurement volume and the nominal sonic heights measured at the base of the boom. The nominal heights were closely matched between the upwind and downwind arrays. I calculated the height difference as
sonic height above height measured at base of boom = boom-length*sin(pitch-angle) = boom-length*sin(lean*cos(leanaz))
where lean and leanaz were determined with the planar fit technique and recorded in the sonic cal files. The boom-length is the distance from the base of the boom to the sonic measurement volume = 1.765 cm.
In the following tables, a positive height difference indicates that the sonic is higher than the base of the boom. The height differences are in cm. The Date/time in the first column is when the new height difference takes effect.
Upwind array
Date/time (PDT) |
Config |
boom ht |
3u |
4u |
5u |
6u |
7u |
8u |
9u |
10u |
11u |
mean |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
June 25 00:00 |
1 |
3.74 m |
1.7 |
-0.5 |
-2.4 |
-2.3 |
3.0 |
0.6 |
0.9 |
-1.0 |
-0.6 |
-0.1 |
July 1 13:00* |
1 |
3.24 |
1.0 |
-0.8 |
-3.3 |
-3.4 |
2.2 |
0.5 |
0.3 |
-2.1 |
-0.8 |
-0.7 |
July 20 16:00 |
2 |
3.64 |
0.4 |
6.1 |
0.4 |
3.0 |
4.0 |
3.1 |
1.5 |
0.2 |
-0.2 |
2.1 |
July 29 12:30 |
3 |
4.83 |
0.9 |
1.6 |
-3.3 |
1.5 |
1.8 |
1.2 |
2.5 |
2.2 |
0.2 |
1.0 |
Aug 9 18:00 |
4 |
6.98 |
6.1 |
7.7 |
7.3 |
4.1 |
4.1 |
7.7 |
2.8 |
4.6 |
1.1 |
5.0 |
* changed upwind array height from 3.74m to 3.24m
Bottom, downwind array
Date/time (PDT) |
Config |
boom ht |
1b |
2b |
3b |
4b |
5b |
6b |
7b |
8b |
9b |
10b |
11b |
12b |
13b |
mean |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
June 25 00:00 |
1 |
3.24 m |
1.4 |
-0.2 |
-1.4 |
0.4 |
0.2 |
-2.7 |
-0.6 |
-4.0 |
2.4 |
1.0 |
-1.5 |
-1.3 |
0.9 |
-0.4 |
July 20 16:00 |
2 |
3.64 |
-1.8 |
-7.7 |
-11.4 |
-7.2 |
-4.8 |
2.2 |
-2.5 |
-7.9 |
-9.6 |
-10.7 |
-7.6 |
-1.3 |
-2.7 |
-5.6 |
July 29 12:30 |
3 |
4.83 |
-2.4 |
-8.7 |
-12.3 |
-8.4 |
-7.0 |
0.3 |
-4.2 |
-10.5 |
-11.2 |
-11.3 |
-7.9 |
-3.3 |
-0.5 |
-6.7 |
July 31 17:00* |
3 |
4.83 |
5.9 |
3.3 |
0.9 |
2.1 |
3.0 |
1.1 |
2.4 |
-1.4 |
0.3 |
-1.2 |
-1.8 |
-2.0 |
-0.5 |
0.9 |
Aug 9 18:00 |
4 |
6.98 |
5.4 |
3.5 |
2.5 |
2.4 |
3.0 |
1.9 |
2.9 |
2.4 |
3.1 |
-0.7 |
-0.4 |
1.0 |
3.1 |
2.3 |
* adjusted height of downwind array sonics to decrease boom sag
Top, downwind array
Date/time (PDT) |
Config |
Boom ht |
3t |
4t |
5t |
6t |
7t |
8t |
9t |
10t |
11t |
mean |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
June 25 00:00 |
1 |
4.24 m |
-2.1 |
-0.9 |
-0.9 |
0.6 |
-0.6 |
-2.1 |
0.7 |
2.1 |
0.4 |
-0.3 |
July 20 16:00 |
2 |
4.64 |
-3.4 |
-2.9 |
-0.9 |
3.2 |
-3.3 |
-4.5 |
-5.4 |
-5.0 |
-4.6 |
-3.0 |
July 29 12:30 |
3 |
5.83 |
-4.4 |
-5.1 |
-3.1 |
0.6 |
-4.7 |
-6.9 |
-6.8 |
-5.7 |
-4.7 |
-4.5 |
July 31 17:00* |
3 |
5.83 |
2.6 |
0.8 |
0.3 |
2.1 |
2.2 |
5.8 |
7.2 |
4.3 |
3.5 |
3.2 |
Aug 9 18:00 |
4 |
7.98 |
3.8 |
2.5 |
3.5 |
2.6 |
2.0 |
2.1 |
3.6 |
3.1 |
4.6 |
3.1 |
* adjusted height of downwind array sonics to decrease boom sag
Profile sonics
Date/time (PDT) |
Config |
1.5m |
3m |
4m |
5.5m |
7m |
8m |
|
|---|---|---|---|---|---|---|---|---|
June 25 00:00 |
1 |
-1.1 |
-2.2 |
-1.0 |
-1.0 |
-0.7 |
1.0 |
|
July 20 16:00 |
2 |
-0.6 |
-2.7 |
-0.2 |
0.0 |
-0.8 |
0.9 |
|
July 29 12:30 |
3 |
0.2 |
-3.1 |
-0.5 |
-1.3 |
-1.5 |
0.6 |
|
Aug 3 09:00* |
3 |
0.2 |
-3.1 |
-0.5 |
-1.3 |
-1.5 |
-1.0 |
|
Aug 3 09:41** |
3 |
0.2 |
-3.1 |
-0.5 |
-1.3 |
0.2 |
-1.0 |
|
Aug 5 15:25* |
3 |
0.2 |
-3.1 |
-0.5 |
-1.3 |
1.4 |
-0.2 |
|
Aug 9 18:00 |
4 |
-0.8 |
-3.7 |
-2.3 |
-2.5 |
-1.4 |
0.3 |
|
Aug 11 12:15* |
4 |
-0.8 |
-3.7 |
-2.3 |
-2.5 |
-1.4 |
-2.1 |
|
* replaced 7m and/or 8m sonics
** moved 7m sonic up