Suchergebnisse

We consider the potential and limitations of widely accepted remote sensing algorithms for detecting forest areas damaged by fires, which allow the monitoring systems to automatically form data about the fire areas and the areas where death of tree stands is subsequently recorded. The resulting size of the detected areas has a measurement error, which is typically determined on the basis of a onetime survey for a large territory and one forest fire season. Depending on the geographical features of the territory, forest fires have specific spatiotemporal and qualitative characteristics, and are accompanied by specific heterogeneous damage to forests, which affect the accuracy of remote detection of a burnt area or firedamaged forest. Hence the use of the unified largearea error estimate for locallevel surveys could lead to inaccurate results. The analysis of space images of forest fund lands in the Tver region for the period 2007-2022 demonstrated the need to establish regional values of the measurement error for fireimpacted areas. By comparing the medium spatial resolution data with the data of high spatial resolution we identify a regional bias, which is significant given the relatively small size of the detected areas. The study demonstrates the expediency of establishing regional error values for measurements of pyrogenic impact on forest areas. By implementing the suggested changes we could improve the accuracy of remotely-sensed estimates of fireimpacted areas and the amount of associated damage to forests.

In 1958 V.F. Perov, staff member of the Khibiny Research and Training Station of the MSU Faculty of Geography, described four snow-ice formations in the Khibiny Mountains and classified them as very small glaciers. Until our research began in 2005, these glaciers were not studied in detail. We used field observations, drilling, GIS and remote sensing methods to study the structure of the glaciers and evaluate changes in their geometry during 60 years. The snow-ice formations were drilled through for the first time and the ice cores underwent geochemical and isotope-oxygen analyses. The thickness of ice kernels varies from 0,2 to 1,6 m. Our investigations showed that despite a slight degradation, the glaciers` area remains relatively stable since 1958. This fact may be caused by the increase in solid precipitation in recent years. According to the analysis of climatic changes, in the early 2000s a decrease in snowfall was observed in the Khibiny Mountains. The maximum snow thickness at the meteorological site of the Khibiny station in 2002-2003 winter period was 55 cm. This could be a factor of more than 2 times decrease of glacier areas during 2000-2010. After 2007 there has been an increase in snow precipitation, and the maximum snow depth of 180 cm was observed in 2020, the absolute maximum for the whole period of observations (1984-2020). According to published data the increase in mean annual temperature at the plains of the Kola Peninsula is 2,3 ± 1°C during the last 50 years. However, mean monthly temperatures of the summer do not rise. We consider that, along with recently increasing snow precipitation, this is exactly what determine rather stable state of snow-ice formations in the Khibiny Mountains, which appeared to be more resistant to climate warming than mountain glaciers.