Subsidence inversion is an inversion caused by cooler heavier air sinking from higher elevations to lower ones. It is associated with a high pressure stable atmosphere; thus, leading to air stagnation.
Sources: Hardy, Colin C., Ottmar, Roger D., Peterson, Janice L., Core, John E., and Seamon, Paula. 2001. Smoke Management Guide for Prescribed and Wildland Fire 2001 Edition. Produced by the National Wildfire coordinating Group Fire Use Working Team.
National Wildfire Coordinating Group. 2012. Glossary of Wildland Fire Terminology. PMS 205. Accessed on 9 September 2013. http://www.nwcg.gov/