Potential forest fire danger over Northern Eurasia: Changes during the 20th century
Abstract
Significant climatic changes over Northern Eurasia during the 20th century have been reflected in numerous variables of economic, social, and ecological interests, including the natural frequency of forest fires. For the former USSR, we are now using the Global Daily Climatology Network (Gleason et al. 2002) and a new Global Synoptic Data Network archive, GSDN, created jointly by NCDC an RIHMI. Data from these archives are employed to estimate systematic changes in indices used in the United States and Russia to assess potential forest fire danger. Within the boundaries of the former USSR, each of the archives, GHCN and GSDN, includes more than 2100 stations with only approximately 1500 of them having sufficiently long meteorological time series suitable for participation in our analyses. We use three indices: (1) Keetch-Byram Drought Index, (KBDI; this index uses only daily data on maximum temperature and precipitation and is developed and widely used in the United States); (2) Modified Nesterov, and (3) Zhdanko Indices (these indices are developed and widely used in Russia; their computation requires synoptic daytime data on temperature and humidity and daily precipitation and snow on the ground). Analyses show that after calibration, time series of the days with increased potential forest fire danger constructed using each of these three indices (a) are well correlated and (b) deliver similar conclusions about systematic changes in the weather conditions conducive to forest fires. Specifically, over the entire Eastern half of Northern Eurasia (Siberia and the Russian Far East) we found a statistically significant increase in indices that characterize the weather conditions conducive to forest fires. These areas coincide with the areas of most significant warming during the past several decades south of the Arctic Circle. West of the Ural Mountains, the same indices show a steady decrease in the frequency of the "dry weather summer days" during the past sixty years. This study supports and justifies our previous findings based on a data set five-times smaller (Groisman et al. 2003) and is corroborated with available statistics of forest fires (Korovin and Zukkert 2003) and with observed changes in characteristics of the forest phenology (Lapenis et al. 2004). Scenarios of the possible future climatic change in Northern Eurasia (IPCC 2001) indicate that the changes will be most prominent in the region. The superposition of these scenarios with the present characteristics of the potential forest fire danger in the Eastern half of Northern Eurasia, show that forest fires themselves may be an important feedback mechanism affecting both the rate and magnitude of the continental climatic changes. An unfortunate corollary is a need to reassess the existing scenarios of future climatic change in Northern Eurasia. These scenarios should include accounting for interactions with the biosphere and its changes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFM.A13B0102S
- Keywords:
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- 1615 Biogeochemical processes (4805);
- 1620 Climate dynamics (3309);
- 1655 Water cycles (1836)