code  description    
A    Accepted value has passed all QC tests applied as represented by the quality level     
B    Sensor buried in snow     
E    Estimated value     
F    Daily value based on the maximum 15 minute mean value     
H    Daily value based on the maximum hourly mean value     
M    Missing value     
Q    Questionable value     
S    Daily value based on sunrise to sunrise     
V    Value spans a range of days (typically a week or less). value is listed in the first day of this range and subsequent included days are coded 'missing'