Marisonde GT Drifting Buoys Quality Control Report

Christopher Harvey

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

September 15, 1995

Report COAREMET 95-15

Version 1.0

Introduction:
The data referenced in this report were collected from the Marisonde GT drifting buoys data 
set (data acquired from Meteo/France) for TOGA COARE during the Intensive Observing 
Period (IOP).  All 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 Marisonde data sets, 
including both flags added by the preprocessor and the analyst.

Statistical Information:
The data from four Marisonde drifting buoys were expected to include observations every 
hour (24 times per day), for all variables except atmospheric pressure which was collected 
every three hours (eight times per day), from 0000 UTC on November 1, 1992 to 2400 
UTC on February 28, 1993.  The result was at most 2880 data values for each variable for 
each buoy.  Time (TIME), latitude (LAT), longitude (LON), wind direction (DIR), wind 
speed (SPD), atmospheric pressure (P), and sea surface temperature (TS) were quality 
controlled.  Some buoys were missing one or more of these variables.  Table 1 provides a 
list of the variables measured at each buoy.  Table 2 provides a listing of the buoys and the 
percentage of data flagged and Table 3 details the distribution of flags and includes the 
percentages flagged for each variable sorted by flag type.

Table 1:  Variables Included at Each Buoy

Buoy
Number TIME    LAT     LON     DIR     SPD      P      TS
							
14414	X	X	X	X	X	X	X
14415	X	X	X	X	X	X	
14416	X	X	X	X	X	X	X
15500	X	X	X		X		X

Table 2:  Availability of Data

                                                 Total
Buoy                        Number of  Number of Number of     Percent
Number  Start Date            Records Variables  Data Values   Flagged
					
14414:	December 9, 1992	1,641	7	11,487	  	0
14415:	January 27, 1993	714	6	4,284		0
14416:	December 8, 1992	1,809	7	12,663		0.0395
15500:	January 27, 1993	515	5	2,575		0
					
Total				4,679		31,009		0.0161

Table 3:  Frequency of Flags Assigned for Each Variable and Flag Type


            Unrealistic      Spike in      Total Number     Percent of Variable
Variable    Movement         Data          of Data Values   Records Flagged
TIME                                           0                 0
LAT            2                               2                0.0427
LON            2                               2                0.0427
DIR                                            0                 0
SPD                            1               1                0.0214
P                                              0                 0
TS                                             0                 0
Total          4               1               5	
				
Percent of 
Total Data 
Flagged      0.0129          0.0032          0.0161	

Summary:
As can be seen from the statistical information, the Marisonde data were in extremely good 
condition.  Only two minor problems occurred resulting in five flags being added.  The 
data analyst does not foresee any problems in using this data.