Two YSI Inc. dissolved oxygen probes (#13341 and #13251) were used in a dual-sensor configuration during the 1997 cruises. Both sensors had electrolyte added before HOT-80. Sensor #13251 started showing large values in its temperature channel during HOT-79, this problem was aggravated after the CTD hit the bottom during the deep cast of HOT-80. The sensor was repaired and calibrated at Sea-Bird on 24 April 1997. Sensor #13341 was also calibrated and inspected on 24 March 1997. This sensor was not affected by the CTD hitting the bottom during HOT-80.
The sensors were empirically calibrated Three sets of parameters were usually obtained per HOT cruise, corresponding to the casts at Stations 1, 2 and 8. Casts from HA-1A and 2A were calibrated with bottle data obtained during these cruises. HA-3A did not have enough bottles for a calibration and was calibrated with coefficients from the following HOT-88 cruise. One set of calibration coefficients was obtained to calibrate the 5 stations of AC-2 cruise. Tables 4.9a and 4.9b give the means and standard deviations for the final calibrated CTD oxygen minus water sample values from the various CTD stations.
Table 4.9a: CTD-Bottle dissolved oxygen per cruise (µmol kg-1)
|
|
|
Station
1, Kahe Point
|
Station
2, ALOHA
|
||||
|
|
|
0 to 1500
dbar
|
0 to 4700
dbar
|
500 to
4700 dbar
|
|||
|
Cruise
|
Sensor
#
|
Mean
|
SD
|
Mean
|
SD
|
Mean
|
SD
|
| 79 |
13251 |
0.00 |
1.22 |
0.07 |
1.07 |
0.21 |
1.07 |
| 80 |
13341 |
0.00 |
1.61 |
0.02 |
1.64 |
0.15 |
1.26 |
| 81 |
13341 |
0.00 |
0.00 |
-0.05 |
1.51 |
0.02 |
1.15 |
| 82 |
13341 |
0.03 |
1.62 |
0.07 |
1.77 |
0.18 |
1.57 |
| 83 |
13341 |
0.02 |
1.81 |
0.00 |
1.92 |
0.17 |
1.67 |
| 84 |
13251 |
0.00 |
0.51 |
0.05 |
1.29 |
0.06 |
0.75 |
| 85 |
13251 |
0.01 |
1.42 |
0.13 |
1.10 |
0.28 |
1.00 |
| 86 |
13251 |
0.00 |
1.08 |
0.11 |
1.28 |
0.40 |
1.14 |
| 87 |
13251 |
No Data |
No Data |
0.08 |
1.32 |
0.15 |
1.06 |
|
88 |
13251 |
0.01 |
0.88 |
0.08 |
0.97 |
0.08 |
0.69 |
Table 4.9b: CTD-Bottle dissolved oxygen at HALE ALOHA and AC-2 (µmol kg-1)
|
|
|
0-1500
dbars
|
|
| Cruise
|
Sensor
#
|
Mean
|
SD
|
| HA-1A |
13251 |
0.01 |
0.68 |
| 80 |
13341 |
0.07 |
1.14 |
| 81 |
13341 |
0.00 |
1.03 |
| 82 |
13341 |
0.07 |
1.63 |
| 83 |
13341 |
-0.02 |
0.55 |
| HA-2A |
13251 |
0.00 |
0.16 |
| 84 |
13251 |
0.00 |
0.56 |
| 85 |
13251 |
0.00 |
0.10 |
| 86 |
13251 |
0.00 |
0.42 |
| 87 |
13251 |
0.00 |
0.02 |
| 88 |
13251 |
0.00 |
0.08 |
| AC-2 |
13251 |
0.01 |
1.46 |
Figure 4.10 shows the CTD oxygen data quality for every 2-dbar bin in each cast at Station ALOHA for cruises 79 through 88.
Figure 4.10. CTD oxygen data quality per cast (vertical bars) and per 2-dbar bin at Station ALOHA during HOT cruises 79 through 88. The tick marks along the x-axis separate different casts. Casts from the same cruise are separated by vertical black lines.
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