Malaita Quality Control Report Parks Camp Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean Atmosphere Response Experiment (COARE) Surface Meteorological Data Processing Center Center for Ocean Atmospheric Prediction Studies The Florida State University November 28, 1995 Report COAREMET 95-19 Version 1.0 Introduction: The data referenced in this report were collected from the 12 meter sailing vessel, Malaita (data acquired from the National Institute of Water and Atmosphere (New Zealand)) for TOGA COARE during the Intensive Observing Period (IOP). The files provided to the DPC contained 20 minute averaged data recorded every 10 minutes. The latitude, longitude, ship heading, ship speed, and rain data were provided in one set of files while the air temperature, dew point temperature, and wind data were in another file. The recording times for the two files were matched and the data combined into a single record for each recording time. The combined data were converted to a standard format and were then preprocessed using an automated data quality checking program. The data were then visually inspected by a data quality analyst who reviewed, modified, and added appropriate quality control (QC) flags to the data. This report summarizes the flags for the Malaita data sets, including both flags added by the preprocessor and the analyst. Statistical Information: The data from the Malaita during the IOP were expected to include means every ten minutes from 0200 UTC on February 14, 1993 to 2400 UTC on February 25, 1993. Time (TIME), latitude (LAT), longitude (LON), platform heading (PL_HD), platform speed (PL_SPD), earth relative wind direction (DIR) and earth relative wind speed (SPD), temperature (T), dew point temperature (TD), and rainfall rate (RRATE) were quality controlled. There were 1,474 total records for the Malaita and up to ten variables for each record resulting in 14,740 values that were reviewed and checked. Table 1 lists the different flags that were assigned to each variable. Table 1: Frequency of Flags Assigned for Each Variable and Flag Type for the Malaita Original Data Failed Were out of T>=Tw>=Td Total Number Percent of Variable Variable Realisric Range Check Bad Data of Flags Records Flagged TIME 0 0 LAT 0 0 LON 0 0 PL_HD 2 2 0.1357 PL_SPD 0 0 T 9 310 319 21.6418 TD 9 310 319 21.6418 DIR 0 0 SPD 0 0 RRATE 18 18 1.2212 TOTAL 20 18 620 658 Percent of Total Data Flagged 0.1357 0.1221 4.2162 4.4640 Summary: As the statistical information indicates, most of the data from the Malaita is considered to be in good condition. A minor problem appeared in the temperature and dew point where a few values failed the T>=Tw>=Td consistency check. Some other temperature and dew point values were obviously bad and were flagged as such by the data analyst. These data values occurred early in the cruise and were unrealistically high (between 35C and 40C). The prescreener flagged these points as being either out of the realistic ranges or greater than four standard deviations from the da Silva climatological mean (1994). Since these data values were obviously not correct and no determination of an instrument failure was possible, the suspect data points were flagged accordingly. Other minor problems occurred in the platform heading where two headings were more than 360 degrees, and in eighteen rainfall rates which were flagged as being out of realistic range. The rainfall rates flagged were in the range of 200mm/hr-400mm/hr which was determined to be unrealistic. In general, the data analyst does not foresee any problems in using this data, however, the temperature and dewpoint data early in the cruise should be avoided. Reference: 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.