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- variables, like OBSTYP, VARIAB, LSMASK, LAT (see 2.1)
- keywords, like synop, u10m, v10m, land, constant (see 2.2)
- statements, like if-then-elif-endif-block (see 2.3.1)
- operators, like and, in,
=,<(see 2.3.2) - built-in functions, like abs (see 2.4)
- actions, like fail (see 2.5)
Variables get their values from IFS. These are compared against the keywords or values given in the blacklist. If the blacklist rule is true, fail-function takes action activating blacklisting flags and returning back to the calling routine in IFS. Note that the blacklist language is case insensitive and no column orientation is required.
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A list of variables that are currently defined in IFS is given below. Adding new variables, see for 5.3.
2.1.1 Report characteristics
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where the refdeg is radius of the circle on the Earth with the (reflat, reflon) as a center point of the circle. The (LAT, LON) is the position of the observation to be checked, i.e. LAT and LON of the report. All values are given in degrees. See also picture 2.1.
Figure 2.1: Schematic view of the rad()-function parameters.
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Variable declaration has to be performed, if data will be passed from an application (like IFS) into the blacklist. This is normally done through external-declaration (see for 4.2 or 5.1). Also, selected variables can be protected by defining them as constants.
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