BODC HEADED DOCUMENT NO. 41600 Applies to BODC Series Ref. Nos.: 29842, 29854, 29866, 29878, 29891, 29909, 29910, 29922, 29934, 442639, 442640, 442652, 442664, 442676, 442688, 442707, 442719, 442720, 442732, 442744 Offshore Sea Floor Pressure Data Screening Carried Out by BODC 1 ================================================================== BODC screen both the series header qualifying information and the parameter values in the data cycles themselves. Header information is inspected for 1) irregularities such as suspect values; 2) inconsistencies between related information, for example depths of meter and sea bed; times of mooring deployment and for start/end of data series; length of record or number of data cycles, the cycle interval, the clock error and the period over which accrued; originator's comments on meter/mooring performance, data quality and parameters measured and the parameters actually present in the data cycles. Documents are written by BODC highlighting irregularities which cannot be resolved. Data cycles are inspected via time series plots of parameters. These plots undergo intrinsic and extrinsic screening to detect suspect values within the data cycles themselves and inconsistencies when compared with adjacent data sets. Values suspected of being of non oceanographic origin may be tagged with the BODC flag denoting suspect value. The following types of irregularity, each relying on visual detection in the time series plot, are amongst those which may be flagged as suspect: Spurious data at the start or end of the record. Obvious spikes of non oceanographic origin. A sequence of constant values in consecutive data cycles. If a large percentage of the data are affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented. Inconsistencies between the characteristics of the data set and those of its neighbours, as for example between the maximum and minimum values of the parameters (spikes excluded) are, where necessary, documented. This intrinsic and extrinsic screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC making are not introduced.