Throughout the centuries, few natural phenomena have inspired as much scientific thought and artistic reflection as clouds.
纵观多个世纪，很少有像云一样激发出了如此众多的科学思想和艺术内涵的自然现象。
More than two millennia ago, Aristotle studied clouds and wrote a treatise addressing their role in the hydrological cycle. But it was Luke Howard, an amateur meteorologist living in England in the early 19th century, who produced the first classification of clouds.
两千多年前，亚里士多德专研云并撰写了一篇论述，阐述了云在水文循环中的作用。但是云的首次分类，是由19世纪初住在英国的业余气象学家卢克·霍华德进行的。
Drawing on his comprehensive records of weather in the London area from 1801 to 1841, Howard identified three main genera, or categories, of cloud: cumulus, stratus and cirrus. Identifying, describing and naming clouds remains critical to the study of weather and climate.
霍华德根据他从1801年到1841年对伦敦地区的综合天气记录，确定了云的三大属或类别：积云、层云和卷云。识别、描述和命名云对天气和气候的研究依然是举足轻重的。
Today, scientists understand that clouds play a vital role in regulating the Earth's energy balance, climate and weather. They help to drive the water cycle and the entire climate system. Understanding clouds is essential for forecasting weather conditions, modelling the impacts of future climate change and predicting the availability of water resources.
今天，科学家们了解到，云在调节地球能量平衡、气候和天气方面起着关键作用。它们有助于驱动水循环和整个气候系统。了解云对于预测天气条件、模拟未来气候变化的影响以及预测可用水资源极为重要。
Music, art and poetry
音乐、艺术和诗歌
The evocative symbolism of clouds has inspired many artists around the world, including poets, musicians, photographers and other enthusiasts. To take just one example, the first orchestral Nocturne by Debussy, entitled Nuages (clouds), is one of the masterpieces of musical impressionism. Photographers are particularly fascinated by clouds, including those who enthusiastically contributed to the WMO 2017 calendar illustrating this year's World Meteorological Day Theme of "Understanding Clouds."
云的象征主义特性启发了世界各地的艺术家：诗人、音乐家、摄影师和其他爱好者。举个例子，德彪西的第一部管弦乐"夜曲"，题为Nuages（云），是音乐印象主义的杰作之一。摄影师们对云尤为着迷，这里面也包括对WMO 2017年挂历积极投稿的人，他们一同诠释了今年的世界气象日主题"观云识天"。
Clouds are also embedded in cultural symbols and habits of thought. In China, "auspicious clouds" represent the heavens and good luck. In some languages people say "she has her head in the clouds" to indicate somebody who is immersed in fantastic dreams or ideas. In the modern world, "the cloud" now refers to that amorphous space that holds, not rain, but Internet resources and digitized data.
云也嵌入到了文化符号和人们的思维习惯中。在中国，"祥云"代表了上天和幸运。在某些语言中，人们说"把头埋在云里"，表示人们沉浸在魔幻般的梦境或思维中。在现代世界中，"云"指一种无形空间，其内蕴藏着互联网资源和数字化资料，而不是雨。
Going digital: an Atlas for the Internet Age
走向数字化：互联网时代的图集
The International Cloud Atlas is the single most authoritative and comprehensive reference for identifying clouds. Its reputation is legendary among cloud enthusiasts. The existing Atlas was first published in the late 19th century. It contains a detailed manual of standards and numerous plates of photographs of clouds and certain other weather phenomena.
《国际云图集》是识别云方面唯一最权威和最全面的参考文献。它在云爱好者心中具有传奇声望。现有的图集首版于19世纪末，内含一个详细的标准手册和大量云及一些其他天气现象的照片。
After the last revision 30 years ago, a fully updated and revised edition will now be launched for World Meteorological Day on 23 March 2017.
继30年前最后一次修订之后，其全面更新和修订版将于2017年3月23日世界气象日推出。
For the first time, the 2017 edition will primarily be an on-line digital product. It offers a treasure trove of hundreds of images of clouds, including a few cloud classifications, such as the volutus, a roll cloud, the contrail, a vapor trail sometimes produced by airplanes, and the asperitas, an undulated cloud. In addition, the Atlas contains important information on other meteorological phenomena such as rainbows, halos, snow devils and hailstones.
2017年版将主要是在线数字产品，这还是第一次。它是一个含数百张云图的宝库，其中包括了几种新的分类，如轧卷云、飞机云（有时由飞机产生的蒸汽尾迹形成）和波状粗糙云。此外，图集中还包含了虹、光晕、雪尘柱和冰雹等其他气象现象的重要信息。
Advances in science, technology and photography prompted WMO to undertake the ambitious and exhaustive task of revising and updating the Atlas with images contributed by meteorologists, cloud watchers and photographers.
这次对由气象学家、云观察家和摄影师提供的图组成的图集进行修改并更新可谓气势宏大、包罗万象，科学、技术和摄影的进步激励着WMO承担起这项任务。
The Atlas also serves as an essential training tool for professionals working in meteorological services and companies and in sectors such as aviation and shipping.
图集还为在气象部门和公司以及航空和航运等行业工作的专业人员提供了必要的培训工具。
Understanding weather and climate phenomena to protect life and property and assist communities to become more resilient is the core mission of WMO. We will continue to assist governments to provide the best possible weather, climate, hydrology, marine and environmental services to protect life and property and to support decision-making.
了解天气和气候现象以保护生命和财产，协助社会变得更有抵御力，这是WMO的核心使命。我们将继续协助各国政府提供最好的天气、气候、水文、海洋和环境服务，以保护生命和财产、为决策提供支持。