P13N

• Nitrate (Fanning / Rutherford - USF) - nitrate and phosphate noisy especially for first half of stations; overall precision poor; deep nitrate trend to high values possibly due to erroneous nitrite. Linear calibration used.
• Phosphate (Fanning / Rutherford - USF) - nitrate and phosphate noisy especially for first half of stations; overall precision poor; deep nitrate trend to high values possibly due to erroneous nitrite. Linear calibration used.
• Silicate (Fanning / Rutherford - USF)
• Oxygen (Fanning / Rutherford - USF)
• TCO₂ (Dickson - SIO) - No adjustments recommended.
• Crossovers:
  

  Crossing #	Old #	Latitude	Longitude	Cruise 1	Cruise 1 Sta	Cruise 2	Cruise 2 Sta	DIC Delta Stdev
  23		30° N	165° E	P13	54,55	P2	48	-5.5 ± 2.1

• Precision of Duplicate Measurements - Duplicate samples were taken at each full station. These were typically a surface sample (in the top 10 m) and a deep sample (usually the from one of the two deepest Niskin bottles). The duplicates were analyzed with the surface pair being analyzed at the beginning of a run, and the deep pair being split between the beginning and end of a run. The standard deviation of a single measurement calculated from these duplicates was:
  
  • "surface" samples (analyzed together) - 1.3 µmol/kg.
  • "deep" samples (analyzed at the start and end of a run) - 2.0 μmol/kg.
  
  The mean difference for the surface samples (first - second) is 0.4 μmol/kg; that for the deep samples is 1.2 μmol/kg.
• Multiparameter Analysis (details) - Mean Difference (estimated - measured) = 1.7 ± 2.9
• Alkalinity (D. Keeling/ Guenther - SIO) - No adjustments recommended.
• Crossovers:
  

  Crossing #	Old #	Latitude	Longitude	Cruise 1	Cruise 1 Sta	Cruise 2	Cruise 2 Sta	TA Delta Stdev
  23		30° N	165° E	P13	54,55	P2	48	12.9 ± 1.2

• Precision of Duplicate Measurements - During each leg of the cruise thirty six pairs of duplicate samples were collected and analyzed, i.e. two sample bottles were filled with water from the same Niskin bottle. The bottle pairs were titrated together, one bottle on the right side of the titrator and the other on the left. The sample standard deviations calculated from the pair data, assuming the left and right sides were not systematically different. Leg 1 there were 33 pairs with s = 1.56 µeq/kg. Leg 2 there were 30 pairs with s = 2.13 µeq/kg. For Leg 1, one duplicate pair was flagged (identified malfunction or error) and one pair was omitted from consideration by the three sigma criterion (side to side delta of 11.7 µeq/kg). For leg 2, three pairs were flagged and the data record was lost for one pair. Two pairs were omitted by the three sigma criterion (delta's of 12.5 and 9.9 µeq/kg).
• Multiparameter Analysis (details) - Mean Difference (estimated - measured) = 1.9 ± 3.6
• fCO₂ (Not Measured)
• pH (Not Measured)