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__15S/01 and P__15S/02 to the updated form, P__15S/01.
|Earth Relative Wind Direction||(DIR)|
|Earth Relative Wind Speed||(SPD)|
Details for the entire cruise including dates, number of records, number of values, number of flags, and percentage flagged are listed in Table 1. A total of 901,351 values are evaluated with 16,819 flags added by the preprocessor and Data Quality Evaluator for a total of 1.87 percent of the values being flagged.
|Number of Flags||Percentage|
|5 Jan 96 - 10 March 96||81,941||901,351||16,819||1.87|
|Variable||G||J||K||S||Total Number of Flags||Percentage of Variable Flagged|
|Total number of Flags||854||3430||12055||480||16819|
|Percentage of All Values Flagged||0.09||0.38||1.34||0.05||1.87|
Value Greater Than 4 Standard Deviations from Climatology ("G" flags):
The preprocessor assigned "G" flags to earth relative wind speed data, sea temperature data, air temperature data, and relative humidity data. The flags identify values that are greater than 4 standard deviations from the Da Silva (1994) climatology for earth relative speed. This test does not necessarily indicate erroneous values, just extreme data.
Erroneous Data ("J" flags):
The Data Quality Evaluator administered "J" flags to relative humidity data. These flags identify data that are of poor quality by visual inspection. Specifically, relative humidity values flagged were in excess of 105 percent. One possible cause of greater than 100 percent relative humidity is a calibration drift on the humidity sensor. However, the relative humidity values do not exhibit daily fluctuations expected as the air temperature changes. Changes in relative humidity as temperature varies should occur even if the sensor had drifted off calibration. Therefore, the "J" flags values were applied and these values should NOT BE USED.
Data Suspect ("K" flags):
The Data Quality Evaluator assigned "K" flags to pressure and relative humidity data with the majority (95.2 percent) being applied to the relative humidity data. These flags indicate that data are suspect and should be used with caution. For the majority of "K" flags, the relative humidity values in the data set were in excess of 100 percent but not in excess of 105 percent. These values also exhibited a signal of the changing air temperature; therefore, the Data Quality Evaluator did ot apply "J" flags. Clearly, the relative humidity sensor on this cruise of the Discoverer had a major problem. We recommend caution be used with all the relative humidity data.
Spike in the Data ("S" flags)
The Data Quality Evaluator applied "S" flags to several parameters in this data set. The flags indicate areas in the data that are drastically out of the current data trend. Spikes are common to electronic data and may be associated with power surges that briefly disrupt the electronic integrity of the AWS systems.
The Discoverer AWS data is generally of excellent quality (with the exception of the relative humidity data) and should be very reliable for the user.
da Silva, A. M., C. C. Young and S. Levitus, 1994: Atlas of Surface Marine Data 1994, Volume 1: Algorithms and Procedures. NOAA Atlas Series. In preparation.
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 32301