Sensor YSI Inc. SN 13-0251 was used for all cruises in 1993. Very low oxygen values were observed in the upper 50-80 m of several casts, specifically, HOT-44, station 1, cast 1 and station 2, casts 10 to 20; HOT-45, station 2 casts 8, 14, 15 and 16; and the single cast made stations 4, 8, 10, 13 and 14; HOT-47, station 2, cast 2. In addition, station 2 cast 2 of HOT-46 showed an abrupt offset in the oxygen trace of about 20 µmol kg-1 between 440 and 750 dbar. These oxygen values were flagged as suspect (see Fig. 4.6). Table 4.5 gives the means and standard deviations for the final calibrated CTD values minus the water sample values.

Table 4.5: CTD minus Bottle O2 (µmol kg-1) Comparison for Each Cruise

 

 

Station 1, Kahe Point

Station 2, ALOHA

 

0 to 1500 dbar

0 to 4700 dbar

500 to 4700 dbar

Cruise

Mean

St. Dev.

Mean

St. Dev.

Mean

St. Dev.

HOT-44

0.64

3.42

0.01

1.22

0.24

1.27

HOT 45

0.01

1.29

0.02

2.27

0.08

1.95

HOT-46

0.00

1.26

0.03

1.37

0.03

1.07

HOT-47

0.02

1.64

0.04

1.97

0.11

1.76

HOT-48

0.00

0.98

 

 

 

 

HOT-49

0.00

1.84

0.09

2.94

0.12

2.71

HOT-50

0.02

2.58

0.05

2.11

-0.019

2.17

 

Figure 4.6 shows the CTD oxygen data quality for every 2-dbar bin in each cast at Station ALOHA for cruises 44 through 50.

Figure 4.6. CTD oxygen data quality per cast (vertical bars) and per 2-dbar bin at Station ALOHA during HOT cruises 44 through 50. 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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