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| Titel |
Smoke injection heights from fires in North America: analysis of 5 years of satellite observations |
| VerfasserIn |
M. Val Martin, J. A. Logan, R. A. Kahn, F.-Y. Leung, D. L. Nelson, D. J. Diner |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 4 ; Nr. 10, no. 4 (2010-02-15), S.1491-1510 |
| Datensatznummer |
250008099
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| Publikation (Nr.) |
 copernicus.org/acp-10-1491-2010.pdf |
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| Zusammenfassung |
| We analyze an extensive record of aerosol smoke plume heights derived from
observations over North America for the fire seasons of 2002 and 2004–2007
made by the Multi-angle Imaging SpectroRadiometer (MISR) instrument on board
the NASA Earth Observing System Terra satellite. We characterize the
magnitude and variability of smoke plume heights for various biomes, and
assess the contribution of local atmospheric and fire conditions to this
variability. Plume heights are highly variable, ranging from a few hundred
meters up to 5000 m above the terrain at the Terra overpass time
(11:00–14:00 local time). The largest plumes are found over the boreal
region (median values of ~850 m height, 24 km length and 940 m
thickness), whereas the smallest plumes are found over cropland and grassland
fires in the contiguous US (median values of ~530 m height, 12 km
length and 550–640 m thickness). The analysis of plume heights in
combination with assimilated meteorological observations from the NASA
Goddard Earth Observing System indicates that a significant fraction
(4–12%) of plumes from fires are injected above the boundary layer (BL),
consistent with earlier results for Alaska and the Yukon Territories during
summer 2004. Most of the plumes located above the BL (>83%) are trapped
within stable atmospheric layers. We find a correlation between plume height
and the MODerate resolution Imaging Spectroradiometer (MODIS) fire radiative
power (FRP) thermal anomalies associated with each plume. Smoke plumes
located in the free troposphere (FT) exhibit larger FRP values
(1620–1640 MW) than those remaining within the BL (174–465 MW). Plumes
located in the FT without a stable layer reach higher altitudes and are more
spread-out vertically than those associated with distinct stable layers
(2490 m height and 2790 m thickness versus 1880 m height and 1800 m
thickness). The MISR plume climatology exhibits a well-defined seasonal cycle
of plume heights in boreal and temperate biomes, with greater heights during
June–July. MODIS FRP measurements indicate that larger summertime heights
are the result of higher fire intensity, likely due to more severe fire
weather during these months. This work demonstrates the significant effect of
fire intensity and atmospheric structure on the ultimate rise of fire
emissions, and underlines the importance of considering such physical
processes in modeling smoke dispersion. |
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