Member's of the WOCE Hydrograhphic 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 March 15, 2001 it was determined that the cruise designator, SR_04_/05, should be added to the DBLK's cruise S__04A/02.
This report summarizes the quality of surface meteorological data collected by the Polarstern (identifier: DBLK) Poldat-automated weather system during WOCE cruises AR_15_/15 and S__04A/02. The data were provided to the Florida State University Data Assembly Center (DAC) in electronic format by G. Koenig-Langlo at AWI-Bremerhaven, Germany. There they were converted to standard DAC netCDF format. The data were then processed using an automated screening program which adds quality control flags to the data, highlighting potential problems. Finally, the Data Quality Evaluator reviews the data and pre-processor flags. Flags are then added, modified, and deleted according to the judgement of the Data Quality Evaluator and other DAC personnel. An in depth description of the WOCE quality control procedures can be found in Smith et al. (1996). The data quality control report summarizes all flags for the Polarstern AWS data and explains reasons why these flags were assigned.
The Polarstern data were expected to include observations averaged every 10 minutes on each of the WOCE cruises. Values for the following variables were collected:
|Ocean Relative Wind Direction||(DIR)|
|Ocean Relative Wind Speed||(SPD)|
|Cloud Base Height||(ZCL)**|
Details of each cruise including cruise dates, number of records, number of values, number of flags, and percentage flagged are listed
in Table 1. A total of 229,573 values were evaluated with 5,652 flags added by the preprocessor and Data Quality Evaluator for a total
of 2.46 percent of the values being flagged.
|CTC||Dates||Number of Records||Number of Values||Number of Flags||Percentage Flagged|
|AR_15_/15||10/18/94 - 11/22/94||5,179||77,685||284||0.34|
|S__04A/02||03/17/96 - 05/20/96||9,493||151,888||5,372||3.54|
|Variable||B||E||G||S||Total Number of Flags||Percentage of Variable Flagged|
|PL_SPD|| 1|| || ||2||3||0.02|
|DIR|| ||545|| ||2||547||3.73|
|TS|| || ||936|| ||936||6.38|
|P|| || ||577|| ||577||3.93|
|T|| || ||348|| ||348||2.37|
|RH|| || ||24||1||25||0.17|
|RAD||3,058|| || || ||3,058||32.21|
|Total number of Flags|| |
|Percentage of All Values Flagged|| |
The prescreener also compares the values of SPD, TS, P, T, and RH to a climatology (da Silva et al. 1994) and assigns the "G" flag for values outside of four standard deviations from the mean. Much of the time the research vessel was located near Antarctica, an area characterized by highly variable weather and a questionable climatology. Consequently, many "G" flags were given to SPD, TS, P, T, and RH. In all cases, the analyst believes that the data represent accurate values. The "G" flags were left simply to call attention to relatively extreme events.
The analyst applied seven "S" flags to isolated spikes in the data. PL_SPD received one "B" flag from the prescreener for a unrealistic value greater than 15 m/s.
Smith, S. R. And D. M. Legler, 1996: netCDF Code Manual for Quality Controlled Surface Meteorological Data. Report WOCEMET 95-4, Center for Ocean Atmospheric Prediction
Studies, Florida State University, Tallahassee, FL 32301
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.