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| Titel |
Effects of lightning and other meteorological factors on fire activity in the North American boreal forest: implications for fire weather forecasting |
| VerfasserIn |
D. Peterson, J. Wang, C. Ichoku, L. A. Remer |
| 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. 14 ; Nr. 10, no. 14 (2010-07-23), S.6873-6888 |
| Datensatznummer |
250008660
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| Publikation (Nr.) |
 copernicus.org/acp-10-6873-2010.pdf |
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| Zusammenfassung |
| The effects of lightning and other meteorological factors on wildfire
activity in the North American boreal forest are statistically analyzed
during the fire seasons of 2000–2006 through an integration of the
following data sets: the MODerate Resolution Imaging Spectroradiometer
(MODIS) level 2 fire products, the 3-hourly 32-km gridded meteorological
data from North American Regional Reanalysis (NARR), and the lightning data
collected by the Canadian Lightning Detection Network (CLDN) and the Alaska
Lightning Detection Network (ALDN). Positive anomalies of the 500 hPa
geopotential height field, convective available potential energy (CAPE),
number of cloud-to-ground lightning strikes, and the number of consecutive
dry days are found to be statistically important to the seasonal variation
of MODIS fire counts in a large portion of Canada and the entirety of
Alaska. Analysis of fire occurrence patterns in the eastern and western
boreal forest regions shows that dry (in the absence of precipitation)
lightning strikes account for only 20% of the total lightning strikes,
but are associated with (and likely cause) 40% of the MODIS observed fire
counts in these regions. The chance for ignition increases when a threshold
of at least 10 dry strikes per NARR grid box and at least 10 consecutive dry
days is reached. Due to the orientation of the large-scale pattern, complex
differences in fire and lightning occurrence and variability were also found
between the eastern and western sub-regions. Locations with a high
percentage of dry strikes commonly experience an increased number of fire
counts, but the mean number of fire counts per dry strike is more than
50% higher in western boreal forest sub-region, suggesting a geographic
and possible topographic influence. While wet lightning events are found to
occur with a large range of CAPE values, a high probability for dry
lightning occurs only when 500 hPa geopotential heights are above ~5700 m
and CAPE values are near the maximum observed level,
underscoring the importance of low-level instability to boreal fire weather
forecasts. |
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