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Satellite Limb Observations of Unprecedented Forest Fire Aerosol in the Stratosphere
Author(s) -
Bourassa Adam E.,
Rieger Landon A.,
Zawada Daniel J.,
Khaykin Sergey,
Thomason L. W.,
Degenstein Doug A.
Publication year - 2019
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2019jd030607
Subject(s) - aerosol , stratosphere , atmospheric sciences , occultation , environmental science , extinction (optical mineralogy) , satellite , altitude (triangle) , atmosphere (unit) , depth sounding , latitude , climatology , meteorology , geology , geography , physics , geodesy , astrophysics , oceanography , mineralogy , astronomy , geometry , mathematics
Intense forest fires in western North America during August 2017 caused smoke plumes that reached the stratosphere. While this phenomenon has often been observed, this particular event caused increases in stratospheric aerosol extinction at higher altitudes with greater magnitude than previously observed in the satellite record. Here we use multiple satellite limb sounding observations, which provide high sensitivity to thin aerosol layers and good vertical resolution, to show that enhancements in aerosol extinction from the fires reached as high as 23 km in altitude and persisted for more than 5 months. Within 1 month, the aerosol is observed to cover latitudes from 20°N to 60°N, which is essentially the northernmost limit of the observations. At midlatitudes between 15‐ and 20‐km altitudes, the sustained level of median aerosol extinction measured at 750 nm increased by almost an order of magnitude, from approximately 10 −4 km −1 to nearly 10 −3 km −1 . Agreement between limb scatter and occultation measurements is generally within 20% despite potential bias due to modified aerosol shape and composition.