Geography 2152F/G Lecture Notes - Lecture 12: Engine Knocking, Pyrolysis, Lightning
4 Dec 2018
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Document Summary
Wildfires through history: the geologic record shows an increase in the amount of charcoal in sediment approximately 10,000 years ago, this suggests high amounts of wildfire activity at the time. Why might there be more fire activity: a warmer and/or drier climate. Increased use of fire by humans for clearing land and for heat, cooking, etc. Elements of wildfires: wildfire requires three elements: fuel, oxygen and heat. 2: this is a chemical process describing the degradation of large hydrocarbon molecules into smaller ones, the process occurs in the presence of heat (i. e. from heat radiating off of nearby flames. ) Combustion phase: the two processes of pre-heating and pyrolysis result in fuel that is prone to ignite, the combustion phase begins with ignition, not all ignitions will result in a wildfire (the vegetation must be dry). Ignition is not a single process; it can occur repeatedly as the fire moves.
