Dynamics of post-fire effects in larch forests of central siberia based on satellite data

Abstract

The article represents the results of Terra, Aqua / MODIS, Landsat-8/OLI satellite data analysis for fire damaged plots in larch forests of Central Siberia. The analysis of averaged surface temperature (brightness temperature) and vegetation index (NDVI) was performed for post-fire circumstances. Estimates of the state and dynamics of fire-damaged vegetation cover were obtained on the basis of inter-seasonal variation of the NDVI index. It was found that post-fire dynamics of vegetation cover determines the surface temperature anomalies within the fire scar plots during at least five years after wildfire impact. It was instrumentally registered that the maximum excess of brightness temperature on post-fire areas can reach up to 11°C comparing to that of background areas under the same conditions. Such anomalies are determined by higher level of insolation due to partial or total tree mortality, as well as by decreasing of on-ground cover thickness after fire impact on grass and moss-lichen covers. During the first year after a fire in larch forests of Siberia, the maximum temperature anomalies of the underlying surface was recorded in the third decade of June. In the course of 2 - 5 years after burning, the maximum temperature anomalies shift to the second or even third decade of July within the phenological season. The suggested approach allows to assess the degree of fire impact on vegetation, as well as to predict changes in the active layer of permafrost soils, which may be a consequence of extra thermal flow at the surface in the circumstances of disturbed larch forests of Siberia.