ENVIRSC 1C03 Lecture Notes - Lecture 7: Vapor Pressure, Fluid Parcel, Humidity
23 Jan 2017
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Document Summary
Understand what humidity is, how it is measure, and how it is related to air temperature. Understand what relative humidity is and its controls. Humidity amount of water vapour in air. Varies around earth, latitudes closer to equator experience higher atmospheric temperatures, more water vapour. Cold temperatures at poles have low water vapour; dry environments. Absolute humidity mass of water vapour/volume of air. Not commonly used because air volume changes constantly. Change in absolute humidity doesn"t mean amount of water vapour changed. Increase in air volume decreases humidity: decrease in air volume increases humidity. Specific humidity mass of water vapour in given air mass (mwater vapour (g) / mtotal air(kg)) Doesn"t change with change in air volume. Vapour pressure amount of pressure exerted on atmosphere by water vapour in air parcel. Dependent on density and temperature of water vapour. High vapour pressure means many water vapor molecules. Equilibrium between evaporating and condensation during saturation.
