Meteorologyatmospheric moisture
Dew Point
The dew point is the temperature to which air must be cooled, at constant pressure, for it to become fully saturated with water vapour. When the ambient air temperature cools to match the dew point, condensation occurs, often leading to the formation of cloud, fog, or dew. A close spread between air temperature and dew point indicates a high probability of fog or low cloud formation.
Key Points
- •Represents the temperature at which air reaches <strong>100% relative humidity</strong>.
- •A close <strong>temperature–dew point spread</strong> indicates a high probability of fog or low cloud.
- •Critical factor in evaluating atmospheric stability and potential icing conditions.
- •When air temperature equals the dew point, visible moisture in the form of cloud, fog, or dew will form.
Exam Relevance
Understanding dew point and the temperature-dew point spread is crucial for predicting the likelihood of fog, low cloud formation, and carburettor icing during flight planning.
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