Introduction to water phase change and importance in meteorology

https://climate.ncsu.edu/edu/Heat

https://www.earthonlinemedia.com/ebooks/tpe_3e/atmospheric_moisture/phase_changes.html

Moisture in the atmosphere

Mixing Ratio (r): The actual amount of water vapor in an air parcel (Mass of water vapor per unit mass of dry air – grams of water/ kg of air) [g/kg]

Saturation Mixing Ratio (rs): The amount of water vapor in saturated air at a specific temperature [g/kg]

Relative Humidity (RH): The RATIO of the amount of water actually in the air compared to the max. amount of water vapor required for saturation at that particular temperature and pressure [%]

  RH = 100% x ( r / rs)