Member's of the Hydographic 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 cruise line designations.
On December 21, 2000, WOCEMET combined the WOCE designators for the A. Von Humboldt (Identifier: Y3CW) cruise AR_06_/01, AR_06_/02, AR_06_/03, AR_16_/04, AR_16_/05, AR_16_/07 and AR_16_/16 to the updated form, AR_06_/01.
On December 21, 2000, WOCEMET combined the WOCE designators for the A. Von Humboldt (Identifier: Y3CW) cruise AR_16_/11 and AR_16_/12 to the updated form, AR_06_/04.
|CTC||Dates||Number of Records||Number of Values||Number of Flags||Percentage |
|08/26/91 - 08/29/91||4678||60814||3122||5.13|
|09/03/91 - 09/12/91||11064||143806||9838||6.84|
|09/17/91 - 10/15/91||27626||359138||23516||6.54|
|AR_16_/07||10/18/91 - 10/19/91||1402||18226||1211||6.14|
|AR_16_/11||09/06/92 - 09/09/92||4327||56806||2260||3.98|
|09/10/92 - 09/25/92||18807||244491||10322||4.22|
Definition of Flags
B: Data out of bounds
F: Unreal ship movement in lat and lon
G: Data 4 standard deviations from climatological mean
H: Discontinuity in data
I: Interesting data point
J: Bad data point
K: Caution/Suspect data
L: Land error
S: Spike in data
T: Time error or duplicate
Z: Data passing all evaluation
Table 2: Percentage of Flags Assigned by Flag Type and Variable
|Variable||B||F||G||H||I||J||K||L||S||T||Total Number of Flags||Percentage of Data Flagged|
|Total Number of Flags||42444||1574||614||4||6||851||2772||200||1739||2||50206||5.30|
|Percentage of Flags Used||4.48||0.17||0.06||0.00||0.00||0.09||0.30||0.02||0.18||0.00||5.30|
Another problem with this data set is the nearly 800 pairs of "F", unreal movement" flags applied by the prescreener to the LAT and LON data. No reason for these observations is known to the DQE, however, slight jumps in measured ship position can cause this problem in minute resolution data. The flags were left as a cautionary note.
In addition to 776 "F" flags, 1597 "S", spike in data, flags were added to LON. These spikes were a result of some points in the original data having degrees longitude, but not minutes or seconds longitude. Thus the data would suddenly jump to the next whole longitude for 1 observation and then return to the pattern of correct longitude observations. Any jump in the data such as the one described would result in "F" flags being applied to both the latitude and the longitude for the points next to where the jump occurred.
The DQE removed these "F" flags when the "S" flags were added.
The last major problem with this data is that DIR and SPD occasionally mirrored the movement of the ship. That is, the DIR sometimes reflected the changes in PL_CRS, and SPD the changes in PL_SPD. Any time DIR or SPD showed patterns similar to PL_CRS or PL_SPD respectively, DIR and SPD were flagged with "K", caution/suspect data, flags. The result was that 953 values of the DIR data and 935 values of the SPD data were flagged with "K" flags.
B: Other cautionary flags:
Varying numbers of "J" flags were added to PL_CRS, PL_SPD, SPD, TS, T, and RH. These were added for the most part because the data seemed to flat-line (i.e., many observations in a row that were the exact same value.
Identical values are rare in minute resolution data; thus the data were flagged as erroneous. Another situation that occurred was that PL_CRS was erroneous, but DIR seemed to be correct, and may have only been off slightly. Any DIR observation in the same record as an erroneous PL_CRS observation was flagged with "J" as well.
100 "L" flags were left by the DQE. These were all applied by the prescreener during the day of 10/15/91. The longitude data jump several degrees, and by doing so, the positions are shifted over land. These values may be considered erroneous.
The data also had a small number of "S" flags applied when necessary. An explanation for the 1577 "S" flags added to LON is in part A of this summary. The rest of the "S" flags are a result of typical problems one has with a large or high temporal resolution data set.
TIME had 2 "T" flags added by the prescreener because of time duplicates.
These data are in good condition. Other than the RAD data, there were no systematic or frequently recurring errors. The DQE cautions the user to regard all the RAD data as suspect. All the other data, with the exception of flagged data, is considered usable.
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.