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| Titel |
Causal relationships versus emergent patterns in the global controls of fire frequency |
| VerfasserIn |
I. Bistinas, S. P. Harrison, I. C. Prentice, J. M. C. Pereira |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 18 ; Nr. 11, no. 18 (2014-09-22), S.5087-5101 |
| Datensatznummer |
250117604
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| Publikation (Nr.) |
 copernicus.org/bg-11-5087-2014.pdf |
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| Zusammenfassung |
| Global controls on month-by-month fractional burnt area (2000–2005) were
investigated by fitting a generalised linear model (GLM) to Global Fire
Emissions Database (GFED) data, with 11 predictor variables representing
vegetation, climate, land use and potential ignition sources. Burnt area is
shown to increase with annual net primary production (NPP), number of dry
days, maximum temperature, grazing-land area, grass/shrub cover and diurnal
temperature range, and to decrease with soil moisture, cropland area and
population density. Lightning showed an apparent (weak) negative influence,
but this disappeared when pure seasonal-cycle effects were taken into
account. The model predicts observed geographic and seasonal patterns, as
well as the emergent relationships seen when burnt area is plotted against
each variable separately. Unimodal relationships with mean annual temperature
and precipitation, population density and gross domestic product (GDP) are
reproduced too, and are thus shown to be secondary consequences of
correlations between different controls (e.g. high NPP with high
precipitation; low NPP with low population density and GDP). These findings
have major implications for the design of global fire models, as several
assumptions in current models – most notably, the widely assumed dependence
of fire frequency on ignition rates – are evidently incorrect. |
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