森林火险气象指数的应用研究

Applied Research on Forest Fire Danger Weather Index

利用全国575个国家级基本气象站1971年1月1日至2005年5月31日的气象观测资料,选用了5种已得到国际普遍认可或我国国家级预警业务中使用的森林火险气象指数计算方法,计算了我国长序列的历史逐日森林火险气象指数,并对这些指数在我国的实际使用效果进行对比分析和应用研究。结果表明:IFFD,INMC,IN,IMN指数可在我国大范围推广使用(除长江中下游及附近地区),其中以IFFD指数总体应用效果最好,IMN指数次之。

Forest fire is one of the main disasters which damage the ecosystem on the earth. Not only vegetation coverage and charcoal storage can be reduced and atmosphere composition can be changed, but also variation of veg etation structure and biological species can be induced and social economy, human health, and even life can be impacted. And the occurrence of forest-fire is very closely related with the meteorological conditions. Until now domestic and foreign meteorologists and forestry experts have developed a lot of forest fire danger weather indices to estimate and predict possibility of ignition, fire intensity and its spread, as well as difficulty of wildfire control. In this study, 5 calculation methods of forest fire danger weather index are chosen, which have been ap- proved universally or used in state-level early warning service in China, using meteorological observation data of 575 national basic meteorological stations from Jan 1, 1971 to May 31, 2005, to conduct contrast analysis and applied research on the practical effects of these indices in China. The purpose of this study is to examine and discover a best method to find forest fire danger weather index which suits Chinese weather and climatic characteristics, and to improve the operational level of Chinese state-level forest fire danger monitoing and early warning. The results indicate that IFFD, INMC, IN and IMN index may be promoted and used in China on a large scale （except in middle and lower reaches and nearby regions of Yangtze River）, in which the overall application effect of IFFD index is the best, and IMN index takes the second place. IFFD index is the best in these five kinds of indices not only because of its practical application effect, and because it has the highest corresponding relations with number of the forest-fire in Northeast China and Southwest China, which are two large key Chinese meteorological service regions of forest fire protection, but also of its construction method. IKBD is not suitable for the most areas of China, but when it is brought into IFFD as a part of drought factor, the practical application effect of IFFD is improved significantly. The practical application effect of IMN is proved to be also good. Its value is closer to the fact than IN, after weighting coefficient is introduced to control the reduction rate of different precipitation to the index. INMC also has good instruction function to forest fire risk, but it is not a patch on IFFD and IMN as a whole. One of the causes is that INMC is insufficient in considering the previous climatic background. In fact, high or extremely high forest fire danger weather rating is related closely to previous precipitation deficit.