How would the wind speed of 20 knots be encoded in column 4?

The wind speed of 20 knots is encoded simply as "20" in column 4. This representation directly corresponds to the actual wind speed in knots without any additional transformation or scaling. The simplicity of this encoding method allows for quick reference and ensures that the data is easily interpreted by individuals using the reporting system.

In aviation weather reporting, clarity and accuracy are paramount, and encoding the wind speed as a whole number (like "20") achieves that goal effectively. The other options represent incorrect formats or scales that do not apply to the standard encoding used in this context. For instance, making it "200" could mislead into thinking it's 200 knots, while "2.0" could imply a smaller unit or a different context. Therefore, the encoding of 20 knots as "20" maintains consistency and clarity in communication within aviation meteorological reporting.