Missing value codes (VMISS)
This line contains a missing value code for each dependent variable in the file.
The number format of the missing value code (number of digits left and right of the decimal point, use of exponential notation or not) specifies the number format of the corresponding data column in the data section. The missing value code is generated by filling all digits with a 9, also for numbers in exponential notation. The absolute value of the missing values code should be at least 1 order of magnitude larger than the largest valid value ever expected.
A flag variable's value can never be missing. But the NASA Ames 1001 specification requires a missing value for each depenendent variable. As far as NASA Ames 1001 is concerned, an EBAS flag variable is just a regular dependent variable, thus we need to define a missing value in line 12 (VMISS). The higest possible value for a flag variable is 0.999990980... (EBAS flags 999, 990, 980 and so on), terefore we should use a missing value of 9.999999999... (one order of magnitude higher then the highest possible value and all digits are nines).
The number of digits needed varies from file to file and from variable to variable (three times the maximum number of flags that will be used at the same time). The needed number format (and thus the missing value) can either be calculated according to the actual file contents before writing the file (the python EBAS IO package does this automatically) or can be set to a constant maximum by the data submitter (e.g. maximum 3 flags allowed, which means 9 digits needed, missing value = 0.999999999).
Please go here for a more in depth explanation of variables and flags.
Mg: range 0.001-3.000: 99.999
SO4: range 0.01-20.00: 999.99
Ozone: range 0-250: 9999
end_time: range 0.000000-366.000000: 9999.999999
end_time: range 0-366: 9999
numflag: 0.000000000-0.999890699: 9.999999999
<missing value tag 1> <missing value tag 2> ... <missing value tag nv>
999 999.9 9.999999999 999.9 9.999999999 999.99 9.999999999 999.99 9.999999999 999.99 9.999999999 999.99 9.999999999 999.99 9.999999999 999.999 9.999999999 999.99 9.999999999 999.99 9.999999999 99.99 9.999999999 9999 9.999999999