P17N

• Nitrate (SIO)
• Phosphate (SIO)
• Silicate (SIO)
• Oxygen (SIO)
• TCO₂ (Goyet - WHOI) - Adjustment of -7 µmol/kg recommended.
• Crossovers:
  

  Crossing #	Latitude	Longitude	WOCE Line	Station(s) used	Crosses with	Station(s) used	Delta TCO2	Stdev TCO2
  47	53° N	152° W	P17N	58,59,66	P16N	78	9	5.1
  59	40° N	135° W	P17N	10	CGC91	37,38,45	7.9	1.5
  60a	35° N	135° W	P17N	12	CGC91	28	3.7	5.1
  60c	35° N	135° W	P17N	28	P17C	17	9.4	3.4
  MEAN							7.5	2.6

• Precision of Duplicate Measurements - No Information.
• CRM Results - No Information.
• Keeling Replicates - Mean difference for 9 samples was -0.98 ± 4.07.
• Multiparameter Analysis (details) - Mean Difference (estimated - measured) = -2.6 ± 6.7
• Isopycnal Analysis - In the region near 37° N, 135° W, the isopycnal analysis indicated that the P17N data are consistently higher (range: 6-16 µmol/kg) than the P17C and CGC91 data (Figure). The CGC91 data agree reasonably well with the P17C results at higher densities, but are somewhat higher at the lowest densities. The crossover and MLR analyses of P17N indicate that the P17N data need to be decreased by 3-10 µmol/kg. An average decrease of ~6 µmol/kg in P17N will account for most of the observed differences with P17C and CGC91, but not all of the observed 6-16 µmol/kg range. The MLR techniques suggest that CGC91 should be increased by 4-5 µmol/kg, but the crossover results are much smaller and none of the techniques indicate a large correction is necessary for P17C. All of these results cannot be reconciled, but a small increase of ~2 µmol/kg in both CGC91 and P17C would minimize all of the observed offsets from the various approaches.
• Alkalinity (Goyet - WHOI) - Adjustment of -12 µmol/kg recommended.
• Crossovers:
  

  Crossing #	Old #	Latitude	Longitude	Cruise 1	Cruise 1 Sta	Cruise 2	Cruise 2 Sta	TALK Delta Stdev
  47	17	53° N	152° W	P16N	58,59,66	P17N	78	-23.6 ± 5.8 (graph)

• Precision of Duplicate Measurements - No Information.
• CRM Results - No Information.
• Multiparameter Analysis (details) - Mean Difference (estimated - measured) = -2.6 ± 5.4
• Isopycnal Analysis - We reexamined the intersection of P17N with P16N to include data from a larger region and a wider depth range than initially considered with the crossover analysis (Figure). The calculated TALK values for P16N also include a +4 µmol/kg adjustment in the TCO₂ values that is proposed from this study. The resulting extended crossover has an average offset of 12 µmol/kg.
• fCO₂ (Not Measured)
• pH (Not Measured)