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5. Comparison with WOA01 climatology 
This technical report is not intended to provide a detailed description of the differences 
between the present and WOA01 World Ocean climatology. However, we want to provide 
the reader with some results of our inter-comparison in order to explain and document 
improvements achieved through the application of our methods of data quality control and 
interpolation. 
The main differences between the present and the WOA01 climatologies are due to 
differences in the (1) data basis, (2) quality control procedure, (3) treatment of systematic 
errors, and (4) spatial interpolation scheme. The data basis used for this study was extended 
through the incorporation of a number of high-quality data-sets. This is important for such 
data poor areas, as central parts of main ocean basins, especially in the South Pacific 
Ocean. The quality control procedure used in this study provides a more elaborate tool in 
identifying erroneous observations by estimating the quality of particular cruises. An 
important deviation from the WOA01 climatology is the treatment of systematic biases 
(errors) in the data, which were calculated relative to the reference WOCE dataset.