Severe Drought, Wildfires Threaten Water Resources
时间:2019-01-13 作者:英语课 分类:VOA标准英语2012年(一月)
Severe Drought, Wildfires Threaten Water Resources
This is Valles Caldera. Actually, it's the giant mouth of a dormant 1 super volcano that last erupted 40,000 years ago. In the millennia 2 since then, the terrain 3 developed high-elevation forests, of abundant water sources and a rich ecosystem 4. Today it's a national preserve.
But last year, over 32,000 hectares of forest in Valles Caldera, as well as in several other states of the American southwest, were consumed by the worst wild fires in a century.
"This burned 43,000 acres [17,000 hectares] in 14 hours. To give you a kind of visual on that, a football field with both end zones and bench areas, burns in 2 seconds," noted 5 Bob Parmenter, chief scientist at Valles Caldera National Preserve.
Parmenter says there are several reasons for that kind of fire: shorter winters with less snow pack along the Rocky Mountains, where many rivers in the American west originate, as well as longer and warmer summers with less rain.
David Brown, a regional climate director for the National Oceanic and Atmospheric 6 Administration (NOAA), says drought is putting heavy stress on water resources.
"One of the most severe droughts in the last 100 years is playing out right now in the southwest," said Brown.
As a result, more than a hundred scientists are working in Valles Caldera in a bid to restore ecological 7 balance to the region, through reforestation and water conservation.
The challenges are huge. A study by the U.S. Geological Survey revealed a 30 to 60 percent decline in the Rocky Mountain snow pack. Gregory Pederson, a climate scientist for USGS, participated in the study.
"All the water resources we need to support the societies and ecosystems 8 comes primarily from snow. For this neck of the world, most of the water comes from snow pack, 60 to 80 percent," said Pederson.
Data from the last several decades indicate that rivers like the Jemez River have lost 40 percent of their waters.
Trees play an important role in water preservation 9, says Bob Parmenter of the Valles Caldera National Preserve:
"The conservative estimate here is that the shading alone increases snow water storage up to 22 percent. As we manage this forest, we can hopefully keep water in the streams as the climate continues to change," added Parmenter.
Parmenter and his team say restoring the forest and the ecosystem in these mountains will help ensure that the region's water resources will survive future droughts and climate change.
The team has begun thinning this forest so wildfires become less likely.
- Many animals are in a dormant state during winter.在冬天许多动物都处于睡眠状态。
- This dormant volcano suddenly fired up.这座休眠火山突然爆发了。
- For two millennia, exogamy was a major transgression for Jews. 两千年来,异族通婚一直是犹太人的一大禁忌。
- In the course of millennia, the dinosaurs died out. 在几千年的时间里,恐龙逐渐死绝了。
- He had made a detailed study of the terrain.他对地形作了缜密的研究。
- He knows the terrain of this locality like the back of his hand.他对这一带的地形了如指掌。
- This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
- We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。
- The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
- Jim is noted for arriving late for work.吉姆上班迟到出了名。
- 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。
- The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
- Each animal has its ecological niche.每种动物都有自己的生态位.
- There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
- Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样,从雨林到半荒漠等不一而足。 来自辞典例句
- The police are responsible for the preservation of law and order.警察负责维持法律与秩序。
- The picture is in an excellent state of preservation.这幅画保存得极为完好。