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专业好文档DesertA scorching sun,an endless sea of sand and a waterless, forbiddingly lonely landthat is the image most people have of deserts. But how true is this picture?炎热的太阳,无穷无尽的海洋沙子和干涸的土地，难以接近地孤独的土地这就是大多数人想象中的沙漠。但这是真实的画面吗? Deserts are dry lands where rainfall is low. This is not to say rain never falls in deserts:it may fall once or twice a year in a fierce torrent that fades almost as soon as it has begun, or which evaporates in the hot air long before it has got anywhere near the earth. It may fall in a sudden sweeping flood that carries everything in its path. Rains may only come once in five or six years for a decade or more.The Mojave desert in the United States remained dry for 25 years. 沙漠就是干涸的土地，在那里很少降雨。这并不是说沙漠从来都不下雨：它可能一年下一次或两次，雨一开始下就在一场奔腾的急流中消失，或者是雨水接近大地之前就被热空气蒸发。它可能加入到突发的、席卷性洪水，即它把它所到之处的所有东西都带走。大雨可能五年、六年、十年或更长时间只来一次。莫哈韦沙漠在美国干涸了25年。Without water no living thing can survive,and one feature of the true desert landscape is the absence of vegetation.With little rain and hardly any vegetation the land suffers under the sun. There are virtually no clouds or trees to protect the earths surface and it can be burning hot.Under the sun,soils break up and crack. Wind and torrential rain sweep away and erode the surface further.没有水,没有东西可以生存,沙漠的一个真实景象是没有植被。雨很少并且几乎陆地上所有植物暴晒在太阳下。几乎没有云或树来保护大地的表面并且它很炙热。在太阳下,土壤龟裂。风和暴雨席卷并且进一步侵蚀地表。 Thirty million square kilometers of the worlds land surface is desert. Throughout history deserts have been expanding and retreating again. Cave paintings show that parts of the Sahara Desert were green and fertile about 10,000 years ago,and even animals like elephants and giraffes roamed the land. Fossil sand dunes found in fertile and damp parts of the world show that these areas were once deserts.三千万平方公里的世界土地是沙漠。纵观历史沙漠的扩张和退去。洞穴绘画表明部分撒哈拉沙漠大约在10000年前是绿色和肥沃的,甚至像大象和长颈鹿等动物在这片土地上漫步。在世界上部分地区肥沃和潮湿的土地上发现的化石沙丘表明这些地区曾经是沙漠。But now the creation of new desert areas is happening on a colossal scale. Twenty million square kilometers, an area twice the size of Canada, is at a high to very high risk of becoming desert. With a further 1.25 million square kilometers under moderate risk, an area covering 30% of the earth land surface is desert, becoming desert, or in danger of becoming desert.但是现在新产生的沙漠地区形成了巨大的规模。二千万平方公里,相当于两倍加拿大面积的陆地,有很高的风险成为沙漠。另有125万平方公里的土地有中度风险成为沙漠，相当于30%的地球陆地是沙漠、或正在成为沙漠、或有风险成为沙漠。 The rate of growth of deserts is alarming. The worlds dry lands are under threat including some of the most important stock-rearing and wheat-growing areas and are the homes of 600-700 million people. These regions are becoming deserts at the rate of more than 58.000 square kilometers a year or 44 hectares a minute.In North Africa at least 100.000 hectares of cropland are lost each year. 沙漠增长的速率是令人惊恐的。世界的干涸土地受到威胁,其中包括一些最重要的 （）和小麦种植地区，那是6亿至7亿人的家园。这些地区以超过58.000平方公里每年或44公顷每分的速度成为沙漠。在北非每年至少100.000公顷的农田流失。 At this rate there is a high risk that we will be confined to living on only 50% of this planets land surface within one more century unless we are able to do something about it.以这种速度，我们将有很大风险在一个多世纪内被限于在这颗星球50%的陆地上生存,除非我们能为这做些什么。Editors note: Judson Jones is a meteorologist, journalist and photographer. He has freelanced with CNN for four years, covering severe weather from tornadoes to typhoons. Follow him on Twitter: jnjonesjr (CNN) - I will always wonder what it was like to huddle around a shortwave radio and through the crackling static from space hear the faint beeps of the worlds first satellite - Sputnik. I also missed watching Neil Armstrong step foot on the moon and the first space shuttle take off for the stars. Those events were way before my time.As a kid, I was fascinated with what goes on in the sky, and when NASA pulled the plug on the shuttle program I was heartbroken. Yet the privatized space race has renewed my childhood dreams to reach for the stars.As a meteorologist, Ive still seen many important weather and space events, but right now, if you were sitting next to me, youd hear my foot tapping rapidly under my desk. Im anxious for the next one: a space capsule hanging from a crane in the New Mexico desert.Its like the set for a George Lucas movie floating to the edge of space.You and I will have the chance to watch a man take a leap into an unimaginable free fall from the edge of space - live.The (lack of) air up there Watch man jump from 96,000 feet Tuesday, I sat at work glued to the live stream of the Red Bull Stratos Mission. I watched the balloons positioned at different altitudes in the sky to test the winds, knowing that if they would just line up in a vertical straight line we would be go for launch.I feel this mission was created for me because I am also a journalist and a photographer, but above all I live for taking a leap of faith - the feeling of pushing the envelope into uncharted territory.The guy who is going to do this, Felix Baumgartner, must have that same feeling, at a level I will never reach. However, it did not stop me from feeling his pain when a gust of swirling wind kicked up and twisted the partially filled balloon that would take him to the upper end of our atmosphere. As soon as the 40-acre balloon, with skin no thicker than a dry cleaning bag, scraped the ground I knew it was over.How claustrophobia almost grounded supersonic skydiverWith each twist, you could see the wrinkles of disappointment on the face of the current record holder and capcom (capsule communications), Col. Joe Kittinger. He hung his head low in mission control as he told Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunday.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause), he can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet (22.7 miles/36.53 kilometers). Here, Fearless Felix will unclip. He will roll back the door.Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).It might not be the moon, but Kittinger free fell from 102,800 feet in 1960 - at the dawn of an infamous space race that captured the hearts of many. Baumgartner will attempt to break that record, a feat that boggles the mind. This is one of those monumental moments I will always remember, because there is no way Id miss this.
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