Notation	Name	Description	Status
0	On direct sun		stable
1	On direct moon		stable
2	On blue zenith sky		stable
3	On zenith cloud (uniform stratified layer of small opacity)		stable
4	On zenith cloud (uniform or moderately variable layer of medium opacity)		stable
5	On zenith cloud (uniform or moderately variable layer of large opacity)		stable
6	On zenith cloud (highly variable opacity, with or without precipitation)		stable
7	On zenith cloud (fog)		stable
8	On zenith haze		stable
9	On direct sun through thin cloud, fog or haze		stable
15	Missing value		stable