摘要：Forest fires are frequent in the Siberian taiga and are predicted to increase in frequency as
a result of increased fire risk under drought conditions, and prolonged fire seasons caused
by climate change. There is, however, some uncertainty as to the extent to which drought
influences forest fire frequency at a regional scale. Here, we present an analysis of
satellite derived soil moisture anomaly data from ERS-1/2 (ERS: Earth Resources
Satellite) scatterometer data and burned area maps from MODIS/AVHRR/ATSR
(Moderate Resolution Imaging Spectroradiometer/Advanced Very High Resolution
Radiometer/Along-Track Scanning Radiometer) over Central Siberia for the years
1992–2000. The purpose of this study is to investigate the relationship of remotely sensed
soil moisture deviations from the long-term mean and fire within the boreal biome on a
sub-continental scale. Results show that wet surface soil moisture conditions limit the extent of burned
area. They can prevent the outbreak of fires but the magnitude of a negative
(dry) deviation does not determine the maximum size of fire affected areas. It is
known from the literature, however, that an ignition is more likely to occur under
low surface wetness conditions, such as those that we observed during July and
August in both permafrost and non-permafrost regions. Although the burned area
under drier conditions in July is lowest over non-permafrost, the actual number of
fires is as high as over continuous permafrost. Approximately 80% of all events
occurred under such conditions during that month. The fire size was below 50 km2 under moist conditions. Larger burned areas have in general
not been detected when the surface wetness deviation exceeded
+5%.
