ENVIRSC 1C03 Lecture Notes - Lecture 7: Fluid Parcel, Vapor Pressure, Humidity

• School: McMaster University
• Department: Environmental Science
• Course: ENVIRSC 1C03
• Professor: Luc Bernier

Document Summary

Humidity: the amount of water vapour in air. Warm air can hold more vapor than cold and as a result, humidity varies all over the earth. Close to equator = higher atm temps, more vapour; growth of lush tropical vegetation. The poles = cold, low water vapour in atm; are dry environments. Humidity refers to water vapour only and not solid or liquid states of water (eg. snow, ice, rain) Specific humidity: represents a given mass of water vapour in a given mass of air. Expressed as the mass of water vapour (g)/mass of total air (kg) Does not change as air expands and contracts. Volume changes are therefore not important, whi(cid:272)h is why it"s a (cid:373)ore relia(cid:271)le esti(cid:373)ate. Vapour pressure: the amount of pressure exerted on the atmosphere by water vapour in an air parcel; in hectopascals (hpa) Is dependent on both the density and the temperature of the vapour.