15 / 60
Ref. No. [UMCES] CBL 2016-016
ACT VS16-07
15
Table 2.
Summary of the mean and standard deviation of offsets between paired Troll 9000 sensor
measures and Winkler reference DO measures during laboratory trials.
Trial ID
Instrument – Winkler DO
mean
s.d.
Observed n Possible n
L_T15_S00
0.004
0.201
51
51
L_T15_S10
-0.289
0.656
36
39
L_T15_S35
0.124
0.076
38
38
L_T04_S00
0.173
0.195
39
39
L_T04_S10
0.130
0.172
36
36
L_T04_S35
-0.142
0.078
37
37
L_T30_S00
-0.040
0.053
40
40
L_T30_S10
-0.045
0.051
39
39
L_T30_S35
-0.104
0.054
40
40
The precision of the Troll RDO sensor was also characterized for each of the nine
temperatures and salinity trials (Table 3). Precision trials were conducted at the start of each new
tank test when conditions were most stable. Instruments were equilibrated in test tanks at indicated
temperature and salinities for 45 min then the subsequent 31 one-minute measurements were used
to estimate average tank DO (mg/L) and its variation over that interval. The absolute precision,
estimated as the standard deviation (s.d.) around the mean, ranged from 0.002 – 0.013 mg/L across
trials with an overall average of 0.004 mg/L. Relative precision, estimated as the coefficient of
variation (CV% = (s.d./mean)x100), ranged from 0.021 – 0.268 percent across trials with an
overall average of 0.062%.
Table 3.
Characterization of the precision of the Troll 9000 RDO sensor over a range of temperatures and
salinities test conditions.
Trial ID
Temperature
Salinity
Dissolved Oxygen Reading
mg/L mean
mg/L s.d.
CV%
n
L_T15_S00
15.44
0.00
9.386
0.005
0.05010
31
L_T15_S10
15.47
8.82
9.463
0.002
0.02127
31
L_T15_S35
15.39
34.20
8.104
0.002
0.03032
31
L_T04_S00
5.40
0.00
12.512
0.003
0.02695
31
L_T04_S10
5.30
8.98
12.160
0.004
0.03011
31
L_T04_S35
5.23
34.77
10.420
0.004
0.03816
31
L_T30_S00
30.22
0.00
4.796
0.013
0.26765
31
L_T30_S10
30.51
9.28
6.832
0.002
0.03590
31
L_T30_S35
30.61
34.43
5.669
0.003
0.05355
31