《科学英语：极端天气强烈影响森林大火的破坏力》由会员分享，可在线阅读，更多相关《科学英语：极端天气强烈影响森林大火的破坏力（7页珍藏版）》请在金锄头文库上搜索。
1、The 2013 Rim1 Fire, the largest wildland fire ever recorded in the Sierra Nevada region, is still fresh in the minds of Californians, as is the urgent need to bring forests back to a more resilient condition. Land managers are using fire as a tool to mimic2 past fire conditions, restore fire-depende
2、nt forests, and reduce fuels in an effort to lessen3 the potential for large, high-intensity4 fires, like the Rim Fire. A study led by the U.S. Forest Services Pacific Southwest Research Station (PSW) and recently published in the journal Forest Ecology and Management examined how the Rim Fire burne
3、d through forests with restored fire regimes in Yosemite National Park to determine whether they were as resistant5 to high-severity fire as many scientists and land managers expected. Since the late 1960s, land managers in Yosemite National Park have used prescribed fire and let lower intensity wil
4、dland fires burn in an attempt to bring back historical fire regimes after decades of fire suppression. For this study, researchers seized a unique opportunity to study data on forest structure and fuels collected in 2009 and 2010 in Yosemites old-growth, mixed-conifer forests that had previously6 b
5、urned at low to moderate severity. Using post-Rim Fire data and imagery, researchers found that areas burned on days the Rim Fire was dominated by a large pyro-convective plume7 - a powerful column of smoke, gases, ash, and other debris8 - burned at moderate to high severity regardless of the number
6、 of prior fires, topography, or forest conditions.The specific conditions leading to large plume formation are unknown, but what is clear from many observations is that these plumes9 are associated with extreme burning conditions, says Jamie Lydersen, PSW biological science technician and the studys
7、 lead author. Plumes often form when atmospheric10 conditions are unstable11, and result in erratic12 fire behavior driven by its own local effect on surface wind and temperatures that override13 the influence of more generalized climate factors measured at nearby weather stations.When the extreme c
8、onditions caused by these plumes subsided14 during the Rim Fire, other factors influenced burn severity. There was a strong influence of elapsed time since the last burn, where forests that experienced fire within the last 14 years burned mainly at low severity in the Rim Fire. Lower elevation15 are
9、as and those with greater shrub16 cover tended to burn at higher severity, says Lydersen.When driven by extreme weather, which often coincides with wildfires that escape initial containment17 efforts, fires can severely18 burn large swaths of forest regardless of ownership and fire history. These fi
10、res may only be controlled if more forests across the landscape have been managed for fuel reduction to allow early stage suppression before weather- and fuels-driven fire intensity makes containment impossible. Coordination19 of fire management activities by land management agencies across jurisdic
11、tions20 could favor burning under more moderate weather conditions when wildfires start and reduce the occurrences of harmful, high-intensity fires.词汇表：1 rim n.(圆物的) 边，轮缘；边界参考例句：The water was even with the rim of the basin.盆里的水与盆边平齐了。She looked at him over the rim of her glass.她的目光越过玻璃杯的边沿看着他。2 mimi
12、c v.模仿，戏弄；n. 模仿他人言行的人参考例句：A parrot can mimic a persons voice.鹦鹉能学人的声音。He used to mimic speech peculiarities of another.他过去总是模仿别人讲话的特点。3 lessen vt.减少，减轻；缩小参考例句：Regular exercise can help to lessen the pain.经常运动有助于减轻痛感。Theyve made great effort to lessen the noise of planes.他们尽力减小飞机的噪音。4 intensity n.强烈，
13、剧烈；强度；烈度参考例句：I didnt realize the intensity of peoples feelings on this issue.我没有意识到这一问题能引起群情激奋。The strike is growing in intensity.罢工日益加剧。5 resistant adj.(to)抵抗的，有抵抗力的参考例句：Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。They imposed their government by force on the resistant population.他们以
14、武力把自己的统治强加在持反抗态度的人民头上。6 previously adv.以前，先前（地）参考例句：The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。7 plume n.羽毛；v. 整理羽毛，骚首弄姿，用羽毛装饰参考例句：Her hat was adorned with a plume.她帽子上饰着羽毛。He does n
15、ot plume himself on these achievements.他并不因这些成就而自夸。8 debris n.瓦砾堆，废墟，碎片参考例句：After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。9 plumes 羽毛( plume 的名词复数 )； 羽毛饰； 羽毛状物； 升上空中的羽状物参考例句：The dancer wore a headdress
16、of pink ostrich plumes. 那位舞蹈演员戴着粉色鸵鸟毛制作的头饰。The plumes on her bonnet barely moved as she nodded. 她点点头，那帽子的羽毛在一个劲儿颤动。10 atmospheric adj.大气的，空气的；大气层的；大气所引起的参考例句：Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。11 unstable adj.不稳定的，易变的参考例句：This bookcase is too unstable to hold so many books.这书橱很不结实，装不了这么多书。The
