关键词: 雷击火, Palmer干旱指数(PDSI), Keetch-Byram干旱指数(KBDI), 大兴安岭林区

Abstract:

The characteristics of lightning fires from 1972 to 2005 and its relationships with Palmer drought severity index (PDSI) and Keetch-Byram drought index (KBDI) in Daxing’anling forest region were analyzed in this paper. The results showed that the lightning fire mainly happened from May to September. A peak of the lightning fires occurred in June, accounting for about 42% of the annual numbers. The maximum burned area happened in May and June, accounting for about 85% of the annual burned areas. Monthly dynamics of numbers and burned area of lightning fires could be expressed as one-humped curves. The monthly dynamics varied with drought indexes. A typical one-humped curve presented with KBDI and the driest months were from May to July, while a weak one-humped curve presented with PDSI, with May drier and June and July wetter. Annual numbers of lightning fires could be closely correlated with PDSI in September (R²=0.47, P<0.01) or KBDI in June and August(R²=0.57,P<0.01), and annual burned areas of lightning fires with PDSI in August(R²=0.20, P<0.01) or KBDI in June(R²=0.40,P<0.01). It was indicated that KBDI was more suitable for simulating the characteristics of lightning fires in Daxing’anling forest region than PDSI.

Key words: lightning fire, Palmer drought severity index (PDSI), Keetch-Byram drought index(KBDI), Daxing&rsquo, anling forest region