我国西南森林雷电环境研究——以四川木里为例

Study on Forest Lightning Environment in Southwest China——Taking Muli of Sichuan Province as an Example

利用四川木里地区历史气候观测资料(1960—2013年)及IPCC对未来(2010—2039年)的气候预估,研究该地森林气候环境;结合森林雷击火发生的必要条件即云地闪数据(2009—2015年),分析气候变化背景下森林云地闪状况。结果表明,木里地区气候呈变干变暖的趋势;该地气温呈较强增加趋势,未来增温趋势略有下降;该地降水量呈弱减少趋势,未来这种减少趋势增强。云地闪有明显的时空变化规律;在年时间尺度上,以2014年为拐点,之前云地闪数量呈现减少趋势,之后增加;在季节分布上,云地闪次数夏季>秋季>春季>冬季;主要分布在4—10月,其中6月份最多,占年总量的33.9%;在空间分布上,随着春、夏、秋季节变化,以该地区28.6°N和100.8°E中轴线为参照线,春秋季云地闪核心区集中在地势相对较低的东南部区域,夏季则扩散到整个地区。云地闪在3、8、10、12月均呈现出与气温变化强正相关、与降水量较弱负相关性,其中尤以3、10月最为突出。因此,随着气候的干暖化,云地闪增加导致的森林雷击灾害极有可能增加。

Taking Muli area of Sichuan province as an example,used historical climate observations during 1960-2013 and the Intergovernmental Panel on Climate Change prediction during 2010-2039 to research the climate change in Muli area,combining with the cloud-to-ground lightning data in 2009-2015 to analyze the change of cloud-to-ground lightning (CG) under regional climate change,the CG was the essential condition of lightning caused forest disasters.The results showed that the climate trends in Muli showed warmer and dryer.The temperature in the area showed a strong increase trend,and the trend of warming in the future decreased slightly;the precipitation showed weak decreasing trend in the past and this trend increased in the future.The CG presented obvious spatial and temporal distribution characteristics.On yearly time scale,regarding the year of 2014 as the inflection point,before this year the CG showed a decreasing trend and after it showed rising trend.For seasonal distribution,the average number of CG change showed in the order of summer > autumn > spring >winter,mainly concentrating from April to October,especially in June,accounting for 33.9% of the whole year.For spatial distribution,taking 28.6 °N and 100.8 °E as the reference line,the core area of CG changed from the southeast in spring to spread to the whole area in summer and then were back to the southeast in autumn.The cloud-to-ground lightning was positively correlated with the temperature and at the same time negatively correlated with precipitation in March,August,October and December,especially in March and October.Therefore,with the climate becomes dry and warm,lightning caused forest hazards by increased CG will very likely to increase in the future.