GEOG 221 Lecture 4: GEOG 221 Lecture 4.2.docx
16 Feb 2013
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Document Summary
Everything that you"re breathing is being affected by the air pollutants in the air. Layer can vary from a few kilometers during the day, sometimes a few hundred meters at night: temperature and mixing height: Either promotes or inhibits vertical mixing through convection. Atmosphere"s ability to mix is categorized by stability . Air parcel: internal pressure > external pressure, expansion occurs. As the air parcel rises, it expands: it"s doing work, pushing outwards: work requires energy, uses internal energy, cools down (temperature drops, rate of cooling is a constant: dry adiabiatic lapse rate (dalr) Dry - not a 100% humidity so not saturated. Rate of temperature decrease in a non-saturated environment that does not exchange energy with its surroundings. Every km it rises up it loses 10 . Actual rate of increase or decrease is called the environmental lapse rate (elr) Stability is the relative tendency for an air parcel to move vertically.
