From VOA Learning English, welcome to As It Is! I’m Mario Ritter.
On our show today, we hear from two weather experts. We hear from one scientist who gets close to tornadoes to learn more about the destructive storms.
“I invented the Doppler on Wheels back in the 1990s because I was frustrated that we couldn’t see enough detail inside tornados and hurricanes.
“我在 20 世纪 90 年代发明了‘有轮子的多普勒’，因为我对无法看到龙卷风和飓风内部的细节而感到受挫。”
But first we hear how climate change may affect wildfires. One, soon-to-be-released report says huge fires may become more common in the future.
Could Warming Temperatures Mean Fiercer Wildfires?
Powerful, intense fires have been burning out of control in parts of the western United States.
In a new report, scientists are predicting more and bigger wildfires over bigger areas and for longer periods in the western United States. But, some people say rising temperatures on our planet could be partly to blame for the severity of wildfires.
Steve Ember has more from a report by VOA’s Rosanne Skirble.
Fires in the United States have gotten worse since the 1970s. Scientists at Harvard University in Massachusetts looked at past weather conditions and wildfires to find out why. Atmospheric chemist Loretta Mickley is a researcher and helped to organize a new study. She says high temperatures and rainfall in other years can create the conditions for large fires.
美国的火灾从 20 世纪 70 年代以来不断加剧。马萨诸塞州哈佛大学的科学家考察了过去的天气条件和火灾，来寻找答案。大气化学学家 Loretta Mickley 是一位研究人员，她帮助组织了一项新的研究。她说，其它年份的高气温和降雨能够为大规模火灾创造条件。
“In some regions, like the Rocky Mountains, really, temperature is the driving force, but elsewhere variables like relative humidity can play a role. If one year is particularly moist, for example, in the Great Basin, Nevada, Utah area, then that will foster a lot of vegetation growth and then the following year all that vegetation can feed wildfires and their spread.”
She and other researchers examined 15 climate models from the Intergovernmental Panel on Climate Change. The panel is the leading international organization that measures climate change. The models predicted average temperature increases of between two and 2.5 degrees Celsius by 2050.
她和其他研究人员检视了跨政府气候变化委员会的 15 个气象模型。该委员会是测量气候变化的主要国际组织。这些模型预测到 2050 年气温将上升 2~2.5 摄氏度。
Loretta Mickley says her team’s research suggests that rising temperatures are linked to fire activity.
Loretta Mickley 说，她的团队的研究表明，不断上升的气温和火灾存在联系。
“So we found, as in the past, temperature is really driving the changes that we predict for the future.”
She says the measurements suggest that the chance of large wildfires will increase by two or three times. Currently, the fire season, the period when most fires take place, is a little over four months. Loretta Mickley says that, by 2050, it will be three weeks longer. She says in the Rocky Mountains, the area burned by fires could increase by as much as four times.
她说，监测数据显示发生大型火灾的概率会增加 2 或 3 倍。目前，火灾季节——多数火灾发生的时段——是 4 个月多一点。Loretta Mickley 说，这到 2050 年将会增加 3 个星期。她说，在落基山脉，发生火灾的面积将增加多达 4 倍。
Fires do more than burn forests. Air quality is also harmed by the huge amounts of smoke produced. In the past 20 years, air quality in many parts of the United States has improved greatly because of federal laws and better technologies. But, Loretta Mickley says, air pollution is an unexpected result of longer lasting, widespread wildfires.
火灾不仅仅焚烧森林，空气质量也因大量产生的烟雾而受到破坏。在过去 20 年，美国很多地方的空气质量因联邦法案和更好的技术而大幅改善。但是，Loretta Mickley 说，空气污染是持续时间更长、传播更广的火灾带来的难以预期的结果。
“But these increases in wildfires could totally disrupt our efforts to clean the air. Last weekend there was an area the size of some states in the eastern U.S. blanketed with unhealthy air over California and Nevada. And, we call this increase in smoke an important climate penalty on air quality.”
That penalty would be air that is two times as smoky as it is today. Ms. Mickley says these estimates suggest the need for better forest management. And, she adds, they send a warning sign to lawmakers and the public to reduce fossil fuel emissions that many scientists believe are warming the planet.
A report on the study will appear next month in the journal Atmospheric Environment. I’m Steve Ember.
A Scientist Who Gets Very, Very Close to a Tornado
Weather experts are able to predict bad weather better than ever before thanks to satellites, high-altitude balloons and radar stations. But for many years these experts have incorrectly predicted tornado formation giving false warnings about 75 percent of the time.
So, scientists are working to improve their tornado predictions.
June Simms reports.
Doppler is a type of radar that identifies weather conditions based on the flow and speed of objects through the air.
Scientist Joshua Wurman was the first to put Doppler radar equipment on a vehicle and drive it into the path of a tornado.
科学家 Joshua Wurman 是第一位将多普勒雷达设备装在运载工具上送进龙卷风行进路线的人。
“I invented the Doppler on Wheels back in the 1990s because I was frustrated that we couldn’t see enough detail inside tornados and hurricanes. We had blurry images of all these things and in order to really understand the physics -- the math of what is going on inside a tornado, how exactly are they forming, how strong are the winds right at the surface are -- we need to get up very, very, close.”
“我在 20 世纪 90 年代发明了‘有轮子的多普勒’，因为我对无法看到龙卷风和飓风内部的细节而感到受挫。我们有关这些东西的图像都很模糊，而为了真正理解其物理特性——龙卷风内部过程的数学表达、它们准确的形成方式、表面风力的大小——我们需要非常、非常接近。”
Mr. Wurman heads the Center for Severe Weather Research in Boulder, a city in the western state of Colorado. He has put his Doppler radar equipment on large trucks. The high-powered antennas continuously turn in circles. They send out radio waves that hit objects in the air -- like raindrops, and birds. Mr. Wurman and his colleagues sit inside the truck and study the computer images formed by the signals that return.
Wurman 先生负责科罗拉多州西部城市博尔德的恶劣天气研究中心。他把他的多普勒雷达设备装在一个大型卡车上。这些高性能天线会持续地转圈。它们发送无线电波来碰触空气中的物体——比如雨滴和小鸟。Wurman 先生和他的同事坐在卡车内，研究返回信号合成的计算机图片。
“I’m seeing it through the computers and through the radar screens, which are making three-dimensional images of the wind and the debris and the rain and hail, flowing around the storm.”
Using information from satellites, stationary radar networks, and computer models, the team finds a storm that could become a tornado and drives the truck right into that area. Doppler on Wheels has been close to over 200 tornados so far.
利用卫星、固定雷达网和计算机模型带来的信息，这个团队发现了一个会发展成龙卷风的风暴，然后把卡车开到了那个区域。“有轮子的多普勒”现在已经近距离观察过 200 多起龙卷风了。
“When we get up close to a storm while it’s in the process of making a tornado we can look at the evolution of the winds near the surface, how that relates to the winds aloft, how the precipitation, the rain and the hail influences whether the air is going up or down, whether it’s cold or warm and how that is causing or not causing a tornado to form.”
The examination combines the Doppler-created images, 3-D maps and information gathered by measuring instruments on the ground in the path of a storm.
Information gathered by the instruments could help builders design stronger homes in areas where such dangerous storms are common.
Scientists are learning more about which storms develop into tornados by studying them from start to end. Mr. Wurman says that radar information has taught them that a “wind surge” could be what causes a storm to turn into a tornado.
I’m June Simms.
Finally, September 11th is Patriot Day in the United States. It is the day when Americans remember the over 3,000 people killed and the thousands injured during the September 11th, 2001 terrorist attacks against the United States.
最后，9 月 11 日是美国的爱国者日。在这一天，美国人纪念 2001 年 9 月 11 日针对美国的恐怖主义袭击所带来的 3000 多死者和数千名伤者。
And that’s our show for today. Join us tomorrow for another As It Is program from VOA Learning English.