寒星物语

http://photography.nationalgeographic.com/photography/photo-of-the-day/cumulus-clouds-sky.html

Cloudy Sky, Location Unknown, 2004
Photograph by Peter Essick

Piles of cotton-like cumulus clouds fill the sky on a clear day. Mid-level cumulus clouds form between 6,500 feet (2,000 meters) and about 20,000 feet (6,000 meters). They form when humid air cools enough for water vapor to condense into droplets or ice crystals. A single cloud can hold billions of pounds of water, but may not always produce rain.

Earth Day, celebrated annually on April 22, marks the anniversary of the 1970 birth of the environmental movement. Scientists warn that rising temperatures worldwide could fuel extreme weather-just one of many damaging effects of global warming.

(Photo shot on assignment for, but not published in, “Signs From Earth: Heating Up, Melting Down,” September 2004, National Geographic magazine)

译文:

多云的天空,地点不详,2004
摄影:Peter Essick

一个晴天，成堆像棉花一样的积云塞满了天空。高积云形成于6500英尺（2000米）至2000英尺（6000米）的高度。当湿润的空气冷却到其中的水汽足够凝结成水滴或者冰晶，便形成了高积云。一片独立的云含有数十亿磅的水，而非总是形成降水。

每年的4月22日是世界地球日，是为了纪念1970年4月22日环保运动诞生而设立。科学家们警告说，全世界范围的气温升高，会加剧极端天气的发生–这只是全球变暖造成的众多破坏后果之一。

(照片来源于《来自土地的征兆：加热，熔化》(2004年9月,国家地理杂志)未发表部分)