Final Corrections

performed at US JGOFS DMO October 28, 1996

From: Lou Codispoti 
Subject: Final Corrections


Dear JGOFS investigator,

This is to inform you that some minor corrections were made to the
JGOFS Arabian Sea nutrient data after the 1996 meeting in New
Hampshire.  It is doubtful that any of these corrections will alter any
of your hypotheses, but they may have some significance in documenting
changes over long periods of time, and in WOCE-style investigations.

The need for these corrections arose, as a consequence of post-cruise
re-calibration of pipets, and because we did not properly account for
the nutrient content of our low nutrient sea-water.

The corrections have already been applied to the US JGOFS Arabian Sea
nutrient data collected with the hydrographic rosette, by personnel at
WHOI who maintain the US JGOFS data. I list them here for your
information.

1) All ammonium and nitrite data from Thompson leg TN053 were
multiplied by 0.997.

2) All ammonium and nitrite data from ALL US JGOFS Arabian Sea cruises
(TN039, 043, 045, 049, 050, 053 and 054) were multiplied by 0.995.

3) ALL phosphate data from ALL US JGOFS Arabian Sea cruises (TN039,
043, 045, 049, 050, 053 and 054) were multiplied  by 0.992.

Corrections 2) and 3) should probably be applied to the ONR data as
well, but I will leave this up to Burt Jones, as I am not exactly sure
how he did his standardizations.  Basically, corrections  2) and 3)
arise from a failure to take into account dilution of the Low Nutrient
Sea Water signal by standards in cases where the LNSW contains
appreciable quantities of nutrients.  The above corrections are pretty
minor within the scheme of nutrient analyses, but we should always
attempt to eliminate such systematic errors.

George and Chris have made these corrections on the US JGOFS Arabian Sea
nutrient data collected from the hydrographic rosette. Trace metal
rosette data and experimental data have not yet been corrected.

Cheers, Lou Codispoti

-- 
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| Louis Codispoti                 | Center for Coastal Physical Oceanography | 
| Research Professor              | Old Dominion University                  | 
| lou@ccpo.odu.edu                | Norfolk Virginia, 23529 USA              |
| http://www.ccpo.odu.edu/        | PH: 804-683-5770  FAX: 804-683-5550      |
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