关键词: 气候变化, 森林火险, 气候影响

Abstract: [Objective] Up to now, researches on forest fire and climate change in China were mainly carried out on regional scale. Thus, it is necessary to study the influences of climate change on forest fire danger on the national scale, which would provide a scientific reference for macro forest fire management in China.[Method] The study area includes main forest distribution regions in China, and it was divided into six regions according to the eco-geographic system in China. The main climatic characteristics and fire danger changes were analyzed over the past 50 years and future period from 2021 to 2050. Surface climate observation data (1961-2010) were collected from 824 basic weather stations, and the data for every meteorological factor were interpolated to grid points (spatial resolution with 0.25°×0.25°) by using distance average weighted method. Simulated climate data (1951-2050) include four climate scenarios (RCP2.6, RCP4.5, RCP6.0, and RCP8.5) and five global climate models (GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, MIROC-ESM-CHEM, and NorESM1-M), and their horizontal resolution was 0.5°×0.5°. Daily fire weather indexes (FWI) were calculated for each grid by FWI system according to the observed data and the calibrated data with the climate models. Mann-Kendall method was used for mutation test.[Result] The average temperature from observed data for the study area in baseline period (1971-2010) showed an upward trend, but there was no significant change in the precipitation. The average temperature in fire season increased significantly from 1961-2010. But the precipitation increased significantly only for the coniferous forest region in temperate arid and desert areas, and no significant changes were found in other forest regions. from 1976-2010, the average FWI for fire season in each eco-geographical region showed an increasing trend. The average temperature in the forest distribution areas would increase by 1.6-2.1℃ from 2021-2050 based on theresult of regional climate models, and the precipitation could increase by 2.3%-4.8%. The average temperature of fire season for each ecological region would increased significantly in 2021-2050, compared with the baseline period. But precipitation would increased significantly just for the coniferous forest region in cold temperate humid zone and broad-leaved forest and artificial vegetation region in north subtropical humid zone. The 95^th percentile FWI from 2021-2050 would increase by 13.5%, 18.9%, 14.9%, and 22.3% for scenarios RCP2.6, RCP4.5, RCP6.0, and RCP8.5, respectively. There are differences in spatial distribution for the FWI increments with different climate scenarios. The days with high fire danger rating would increase significantly for southern and southwestern regions.[Conclusion] The simulated temperature and precipitation data are almost consistent with the observed data in history. From 2021-2050, the average temperature would increase in forest regions, and the climate in fire season would show a warming and drying trend. The fire weather indexes showed an increasing trend from 1976-2010, and they would continue rise from 2021-2050. The fire weather indexes would increase more significant in the south than in the north China. North and southwest China would be the key areas for forest fire prevention in the future. At present, the climate model cannot simulate extreme climate events well, which must affect the accuracy of the fire danger analysis. But the result can reflect the tendency of fire weather change. In the future, more attention should be paid to the study on the influences of extreme climate events on forest fire risk and potential fire behavior.

Key words: climate change, forest fire danger, climate impacts