Discoverer Quality Control Report
Daniel M. Gilmore and Shawn Smith
World Ocean Circulation Experiment (WOCE)
Surface Meteorological Data Assembly Center
Center for Ocean-Atmospheric Prediction Studies
The Florida State University
December 21, 2000
Report WOCEMET 96-4
Member's of the WOCE Hydrographic Project Office (WHPO) and WOCEMET met at the 13th Data Products Committee (DPC) meeting in College Station, TX to discuss reconciliation of the WOCE cruise line designators. This was done in anticipation of the future release of version 3 of the WOCE global data set, and resulted in changes to several WOCE cruise line designations.
On December 21, 2000, WOCEMET combined the WOCE designation for the cruises P__18N/00 and P__18S/00 to the updated form, P__18_/00.
The data referenced in this report were collected from the research vessel Discoverer (call sign WTEA) SEAS Meteorological Package (data acquired from A. Dickson at the NOAA Pacific Marine Environmental Laboratory) for WOCE. The original hard copy data were digitized and then converted to a standard format. The data were then pre-processed using an automated data checking program. A visual inspection of the data was then completed by a data quality analyst who reviewed, modified, and added appropriate quality control (QC) flags to the data. Details of the WOCE QC can be found in Smith et al. (1996). This report summarizes the flags for the Discoverer data set, including flags added by both the pre-processor and the analyst.
The data from the Discoverer were expected to include observations taken every 10 minutes. The cruise began on January 31, 1994, ended April 27, 1994, and covered two WOCE hydrographic sections. Time (TIME), latitude (LAT), longitude (LON), wind direction (DIR), wind speed (SPD), atmospheric pressure (P), and sea temperature (TS) were quality controlled. A total of 75,250 values were reviewed and checked and 1,954 flags were added resulting in 2.70% of the data being flagged. Table 1 details the distribution of flags and includes the percentages flagged for each variable.
|Table 1: Frequency of Flags assigned for Each Variable and Flag Type|
||Unreal Movement||>4 S. D.
||Percent of Variable Records Flagged|
Unlike atmospheric pressure and wind speed, the "G" flags added to sea temperature were not added because the data were significantly out of range. Rather there is very little deviation from climatology to define a standard deviation for sea temperature. So if a sea temperature observation was off by only 2 degrees, it may still be 4 standard deviations from climatology, and be flagged accordingly. This situation was not atypical for this data set.
The only other problem with the data is 7 "F", unreal movement, flags added to both latitude and
longitude. There is no explanation given for and no data to dispute the flags, so the analyst has
chosen to retain these "F" flags.
Virtually all the data in this set is good data. The analyst recommends using this set and foresees no additional problems.
Smith, S.R., C. Harvey, and D.M. Legler, 1996: Handbook of Quality Control Procedures and Methods for Surface Meteorology Data. WOCE Report No. 141/96, Report WOCEMET 96-1, Center for Ocean Atmospheric Prediction Studies, Florida State University, Tallahassee, FL 32310.