气候变化对内蒙古草原火灾的影响

Impact of climate change on the grassland fires in Inner Mongolia

通过对研究区81个气象站1981-2010年的气象资料和收集的草原火灾资料统计分析,得出内蒙古草原区年平均气温呈直线上升趋势,增温率为0.337℃·10a-1;年降水量呈减少趋势,1999年以后年降水量减少40.8mm;多年平均风速呈减小趋势;气候经历了冷干-暖湿-暖干期。受气候暖干化的影响,内蒙古草原植被退化,牧草高度、盖度和地上生物量降低,地面可燃物载量也降低,使草原火灾呈逐年递减趋势。引发草原火灾的火源雷击火和境外火明显减少,机车失火和吸烟引发的火灾仍高居榜首。从地域分布上看,内蒙古东北部草原火灾的次数在减少;西部地区受降水增多和国家实施的生态建设工程的影响,部分地区植被得到恢复,地面可燃物增多,草原火灾呈上升趋势。风速减小,牧草的及时刈割,牧区的科学管理和牧民防火意识的提高,是近几年没有重特大草原火灾发生的主要原因。

Meteorological data and prairie fire records of 81 weather stations from 1981 to 2010 were analyzed. The average temperature in Inner Mongolia grassland appeared linear upward trend,increasing rate was of 0. 337℃ ·10a1; annual precipitation tended to decrease,annual precipitation since 1999 reduced by 40. 8mm; annual average wind speed appeared decreasing trend. It experienced a cold and dry climatewarmwarm and dry period. Affected by climate warming and drying,the grassland in Inner Mongolia,degraded pasture height,coverage,aboveground biomass and ground fuel loads were reduced,so that grassland fires were showed gradually decreasing trend. Prairie fire caused by lightning fires and the fire coming from border was significantly reduced,locomotive fire and smoke caused fires were still topped the list. From the view of geographical distribution,the number of grassland fires in northeastern Inner Mongolia reduced; in the western region precipitation increase and implementation of the national ecological of construction projects restorated the vegetation in some areas,so ground fuel increased,the grassland fires increased. Wind speed decrease,the timelyincrease mowing grass,pastoral nomads of scientific management and fire prevention awareness,were the main reasons for the no major grassland fire in recent years.