From Ocean Teacher Library
Intercalibration Exercises for Marine DataContents |
Background
Because error in marine survey data is introduced by many factors outside the laboratory, including sampling errors, natural variability of the medium, and storage problems, it useful to perform tests of the overall summation of these errors. This exercise, performed quite rarely, is called intercalibration. Typically a number of vessels converge on a single station at sea and sample "the same location" simultaneously, and subsequently measure the same parameters on the presumed identical water samples. Alternately, the samples can be split and transferred between vessels at sea or on shore.
SKAGEX Intercalibration Transect
SKAGEX was a Nordic nations marine research program at the entrance to the Baltic in the late 80s/early 90s; the data are presently held at ICES. During the work, the various institutions were able to conduct a full-scale intercalibration exercise, consisting of 13 vessels sampling the ocean at the same times and stations along a transect from Norway to Denmark. This technical report documents the results of that exercise for salinity, temperature, nitrate, phosphate and silicate (shown here). Examination of this document (actually a photocopy) is a very good example of the vagaries of finding and using older, hard-copy data. Imperfections in the images are typical of the quality usually found in such legacy data. You can see from this sample figure that there was considerable spread in the reported values.
SKAGEX Intercalibration Report
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Information about this article
Short title: Intercalibration Exercises
Description: none
Expertise level: beginner
Author: Murray.Brown
Approval status: approved
Approved by: Murray.Brown
Last change: 2008-9-10
Subsection of: Marine Data Quality Assurance
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