Theme: East-West Interdisciplinary Boreal Forest Fire Experiment, Part 4 Moderator: V.V. Furyaev and Eino Mälkönen 10.8.1995 9:30 Room: U16
Gaseous Crownfire Emissions from the Bor Forest Island Fire
Cofer III, Wesley R., Winstead, Edward L., Stocks, Brian J., Goldammer, Johann G., Cahoon Jr., Donald R., Levine, Joel S.
Measurements of gaseous carbon dioxide, carbon monoxide, hydrogen, methane, and total non-methane hydrocarbons were made in the convection smoke column of a high-intensity experimental stand-replacement fire as part of the first joint East-West fire research activity organized under the Fire Research Campaign Asia-North (FIRESCAN). The Bor Forest Island Fire (60°45’N, 89°25’E) was conducted in the Siberian taiga on 6 July 1993, and involved the burning of about 50 ha of 130 year old, 20 m high, Scots pine (Pinus sylvestris) on a forest floor covering composed essentially of lichen (Cladonia sp.) residing on 57 cm of partially decomposed organic matter. A Russian MI-8 helicopter was fitted with NASA-Langley Research Center smoke sampling equipment and used to collect emissions released during three defined stages of the Bor fire: (1) Flaming groundfire prior to migration into the tree crowns; (2) a period of crownfire predominance; and (3) smoldering at the end of the fire. Emission ratios (ER’s) were determined based on CO2 normalization (ER = dx (plume Background)/dCO2 (plume background)). Mean ER’s determined for CO, CH4, TNMHC, and H2 for the flaming groundfire stage of the Bor fire were similar to those determined previously for flaming combustion in Canadian boreal logging-slash fires. ER’s determined for CH4, H2, and TMNHC from smoke enriched in crownfire emissions remained consistent with those obtained for flaming combustion in the Canadian boreal system, however, ER’s determined for CO were numerically higher and much closer to those determined for smoldering phase combustion (a less efficient combustion). The ER’s determined for CH4, H2, and TNMHC during the final smoldering stages of the Bor fire again remained consistent with the boreal smoldering results determined from the Canadian fires, while the mean emission ratios determined for CO were the highest we have ever measured (0.33 ± 0.05)
Key words: vegetation fire emission, crown fire emissions.
Correspondence: Wesley R. Cofer III, NASA-Langley Research Center, Atmospheric Sciences Division, Mail Stop 483, USA-Hampton, Virginia 23681