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Evidence of significant large‐scale impacts of boreal fires on ozone levels in the midlatitude Northern Hemisphere free troposphere
Author(s) -
Lapina K.,
Honrath R. E.,
Owen R. C.,
Val Martín M.,
Pfister G.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl025878
Subject(s) - middle latitudes , troposphere , boreal , environmental science , atmospheric sciences , northern hemisphere , climatology , southern hemisphere , taiga , mixing ratio , latitude , geography , geology , archaeology , geodesy , forestry
Summertime observations of O 3 and CO made at the PICO‐NARE station during 2001, 2003, and 2004 are used to assess the impact of boreal forest fires on the distribution of O 3 mixing ratios in the midlatitude Northern Hemisphere (NH) lower free troposphere (FT). Backward trajectories were used to select measurements impacted by outflow from high‐latitude regions. Measurements during these periods were segregated into two subsets: those obtained during periods with and without apparent significant upwind fire emissions. Periods affected by fire emissions were identified based on enhanced CO levels confirmed by global simulations of fire emissions transport. During fire‐impacted periods, O 3 was shifted toward higher mixing ratios, with medians significantly higher than in periods without detectable upwind fire impacts. This implies a significant impact of boreal wildfires on midlatitude lower FT background O 3 during summer. Predicted future increases in boreal wildfires may therefore affect summertime O 3 levels over large regions.