GEOG209 Lecture 4: Precipitation Note
13 Jun 2016
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Warm air is less dense, and more water vapour can be evaporated into it. A: add moisture to air to decrease temperature, more moisture makes it more dense. The amount of water vapour (moisture) inside a hypothetical air parcel or container (right) is quantified using the vapour pressure (e), which is the contribution of water vapour to total atmospheric pressure. The vapour pressure increases with increasing evap. , up to the point of saturation (e s) Saturation is where evaporation and condensation are in balance. For an air parcel with fixed moisture content: calculate relative humidity (rh) for air outside (-10c, calculate rh for air inside (20 c) Add moisture to air, better for skin // quantifying moisture. Expansion due to decreasing pressure leads to cooling b/c the same amount of heat is distributed over an increased volume. The rate of cooling of air parcel depends on whether condensation is occurring or not.
